So more often than not when I go to the general discussion forums I am greeted with "Darius is OP" threads (along with other crying threads) and sweet baby Jesus does it get out of hand. Sometimes they can be legit complains about overpowered traits of some characters but more often than not it is just players complaining about annoying traits of a character that doesn't necessarily make them overpowered but a nuisance at times. When it comes to Darius - it can get downright embarrassing how players complain.
One of the biggest embarrassments of this game is how the playerbase is so damn ignorant about pretty much everything. They call for balance on things that don't require it. They flock like sheep to everything that "pros" say and then convince themselves they know of things they don't actually know. So many damn times have the "pros" been proven wrong about champions that at this point it's not even funny. So many times have players in the forums complained about champions being overpowered or underpowered and then they're forced to eat their words when it's revealed they've been wrong this entire time.
There is a massive list of champions that have gone through this. There was a time that Jax was said to be underpowered and people complained when Riot believed him to actually be overpowered and thus nerfed him. Players complained so much that Riot rebuffed Jax and then Jax was used competitively and crushed everyone that Riot ended up doing the same exact nerf on Jax and people felt it was justified. After tank/AD Gragas was nerfed there were a bunch of players saying that Gragas was useless now and he needed buffs. Riot kept telling the NA playerbase that if Gragas was buffed then EU would have a massive meltdown due to him being op. Players didn't listen of course until they saw Gragas being played in the following tournament and he crushed as AP. Hell I can go on with this about pretty much every damn champion at some point.
Sure there will be some people who will say that I do that too. Well I can't deny that at some points I'll be very strongly opposed to something but that's because I've already tested things out myself...or something is painfully obviously not going to work. I had a few of those things but after I learned the hard way I sit back and try to observe things before I call them out. If anyone remember how I acted when I opposed Lane Udyr some long time ago - that was rather shameful. That said - since then I've adopted a more "slow and steady" approach to things that are out of the ordinary. Only if something is a very obvious extreme case of godliness or crap do I do so otherwise.
I felt rather vindicated that Skarner became one of the most used junglers again after a long absence of him not being used. I had Skarner in tier 1 for the longest of times and players would say things like "lol this tier list is stupid he has skarner above Shyvana/Nautilus" or some stupid crap like that. I would be asked to reconsider why I have Skarner in tier 1 and then be given a list of problems about him. If you have the time you can scour my tier list topics and read the comments. You may find them still there. Of course I ignored them because I knew Skarner was a very powerful jungler for the current meta. Then he is used by pros and all of a sudden everyone realizes he's op. One of the downright most upsetting things that I ever read was someone complaining to me about how I should raise Skarner higher in tier 1. You know I've had him in tier 1 since forever and now after being told so many times to take him down...I should raise him up?
People need to learn how a champion becomes legitimately overpowered and/or needs nerfs/fixing badly. There are three balance factors (they are all intertwined in some way) that manage this. They are design, numbers and toxicity.
Balance by Design
This one should be rather simple to understand. It's just how well the kit works within the champion and how it holds itself up with the current meta. There are some very well designed champions in this game that, unless they are purposely neutered in their numbers, will always find a place in the game.
Champions designed with a strong emphasis on their kits are often packing utility of some kind or synergy within their abilities thus they're able to be given a role and actually fulfill it. The best examples of this are champions such as Jarvan, Blitzcrank, Leona, Trundle, Lulu, Pantheon, and Orianna.
The thing with well designed champions is that they can become obscenely overpowered if their numbers are off. This doesn't take too long to figure out though. Often times champions with a well designed kit that's balanced with strengths and flaws can simply have the proper things observed and tweaked around. That's the key thing though - the kit can't have tons of things in it otherwise balancing it with numbers is going to be a nightmare.
Let's use Pantheon's balance cycle as an example for this. When Pantheon came out he went ignored for quite awhile. Then a bug where his E did like 1000% of his damage arose and that was fixed. However, people had begun to play him more because of that and they quickly realized his role in the game was obscenely powerful. He is a lane dominator and he takes that domination to the other lanes after slaughtering his opponent - especially if they're squishy ability power characters or ranged characters (the meta at the time). The thing is - he was designed to do this. He was designed to get in your face and tear it off. So Riot went about nerfing and went overboard with it. Pantheon's numbers were so bad that he couldn't even do what he was supposed to do. Riot kept going back and forth with his buffs and nerfs that he would constantly go from being overpowered to underpowered. Eventually it has led to what he is now and he's actually a really good champion for the role he is meant to have. He's been relegated to being a situational pick but one can't argue that he's obscenely over-powered or grossly weak.
Some may find it unusual that I put Trundle in the well designed category but he truly is. He was designed to be a debuffing tanky jungler. He makes mincemeat out of tanks and is one slippery bastard. He's never needed to be rebalanced but it is true that he wasn't used in Season 2. That's not that the champion is bad but that his design, while good, doesn't fit the current meta. Some champions can be well designed but still never be used simply because the role they're meant to fill isn't necessary at the time. If the meta were to shift to teams having only one tanky character and needing a beefy jungler - then Trundle will make his return.. He's amazing at kiting, map control and being the singular tank of a team. These were traits that were favored in Season 1 and thus he was one of the most used. There are other champions like this that have functioning designs and have balanced numbers but they simply won't be used because the current meta flavors don't call for them. A few of these champions are champs like Brand (designed to dish out combo damage and only damage), Renekton (itemization doesn't love him), Galio (lane tanks like him aren't favored) and Swain (pimpitude still being learned by players).
In short - Well designed champions are carried by the fluid functioning of their kits and are overpowered if the numbers are obscene. Only when their numbers are purposely broken do they became rather weak and even then some can still retain some form of function. They're very susceptible to the callings of the meta.
Balance by Numbers
Now this is still "technically" about design but more about bad design. Some champions are so badly designed that they can only be saved by numbers. This in turn ends up causing a lot of balance issues along the way.
Sometimes these champions were designed with good ideas in mind and they turned out to not actually work out. Some of these champions though, in my opinion, were just whipped up with no idea in mind and whatever happened with them. Truth be told though this is more relegated to older champions than it is to new champions. Riot has been making champions that, more or less, have good designs.
That said some of the champions with the most haphazard designs of all time (some which have been remade or changed a bit) are champions like Sion, Gangplank (old), Kassadin, Udyr, Volibear and Olaf (release).
Both Kassadin and Sion are the prime examples of this. Kassadin was intended to be some sort of melee anti-mage caster thing and had items like Phantom Dancer and Wit's End as his core recommended build. That didn't work out of course and thus his design was a failure. However the base values on his abilities were strong and people figured out that building AP on him was the way to go. We've seen him go back and forth from being ungodly to crap only to return to ungodly with a minor numbers buff or just having others be nerfed (thus he's technically mathematically superior again). Then we have Sion. Even to this day I don't know what he was meant to do. His abilities don't function with each other properly aside from two of them per build. If you go AD on him then two of his abilities will be laughably weak and if you go AP then his other two abilities will suck. But we've seen it happen where he's a dominant laner because he deals so much damage and he's picked above others (this was some time ago) and thus needed nerfs. They tweak his numbers around a bit and then he's completely neutered. The champion has a kit that doesn't function and tweaking his numbers will either make him really strong or really weak.
I feel before people blow up on me that I should explain why I put Olaf there. For me he's a champion that encompasses something Kassadin had to do but to a bigger extreme. See he came out with the intention of being a laner (if the spotlight is to be believed) but he came out with terrible lane control and severe mana problems. He sucked as laner back then unlike now. So when he was released, people didn't actually use him. Then someone figured the proper way to make him jungle (dangerous as hell though) and realized just how ungodly fast he was and how that made him overcome his early game weaknesses and reach his late game faster. The guy had good damage and numbers but he just didn't have a way to make use of them. The guy was designed as a laner and sucked at it because of the weaknesses he was granted. However his strengths and numbers that could function worked out elsewhere and thus Jungle Olaf was born. This has happened before with champions with shafted numbers before. Champions with such poorly functioning early games are forced to find an alternative way to be enabled. Their early numbers are so bad but their later numbers are so good (Nautilus). Even well designed champions who are misguided in their design can figure out an alternative to make them work out. This applies to well designed champions too and can make them even more powerful (like Zyra).
In short - poorly designed champions (or misguided) are carried by how good their numbers are. Every meta shift has the chance of making some of these champions obscenely powerful again or complete crap. New champions that can fill a similar role to them also have the chance of making these champions no longer viable or champions that outright counter them. It is a good thing only older champions seem to suffer this as Riot has vastly improved how they make champions. Champions simply need to have their kits tweaked instead of chancing it all on numbers.
Balance caused by Toxicity
This one is a very iffy thing to discuss to be honest. Just off the bat some of the most toxic champions in this game are Tryndamere, Shaco, Teemo, Nidalee, Vladimir, Irelia, Gangplank (old), stealth, Poppy, and the list goes on.
In short these things are considered toxic because they're outright stupid or can turn into something potentially catastrophic if there is a meta shift. I didn't list all the toxic champions but toxic champs are generally the champions that need constant restructuring pretty much every now and then or simply allow every little reasonable counter-play. These champions might even become stupid again during Season 3.
Shaco is one of the best examples of this actually. When he was released he was one of the most dumbshit champions ever. He was just too difficult to deal with. You could stop him but it was such a pain in the ass. He could do so much stupid crap including stacking auras and sunfire capes with his own clone and his numbers were obscene. Eventually he was gutted for season 1. He was later buffed but it wasn't enough. Then season 2 happened and he could do that 2 minute double buff crap where he'd be level 3 and his opponents were barely getting their first minion kill. So they nerfed him again and again. Shaco's design is so toxic that, even with any changes, if the meta shifts - he can become stupid as hell again. You can't properly balance a character like him. He has so much stuff thrown on him that it becomes a mess.
Vladimir...if I recall correctly, Morello once stated that he regrets letting Vladimir be released. He's another one of those champions that has toxic gameplay. He was stupid beyond hell when released and went through so many phases of being nerfed, not used, then returning and being unbearable. He was stupid when you could stack spell vamp, he was stupid when you could build him tank, and he still is rather stupid in some doses. This champion will, at some point, need to be rebalanced again if a meta shift ends up favoring him.
Teemo is another good example. It's not that he's been beyond overpowered or beyond underpowered - it's that no matter what this champion does he's so annoying and so potentially stupid that he changes the way some games can be played. A shift in the meta can potentially make him powerful especially a split pushing or kiting meta. That said Riot figures they need to nerf him for Season 3. Oracles is being nerfed therefore he could become a nightmare as his mushrooms will go unchecked and the hurricane item could make him stupid too.
Tryndamere is just one of those champions that either works too good or just sucks. He isn't so much obscene as he is difficult to balance because of the inherent extremes of his kit. Becoming immune to death is rather extreme as far as balance goes.
Irelia is, aside from some range being gifted to her, has a kit that has a lot going for her. There's just a lot of things about her that need to be balanced and some of them are rather extreme things that no other champions have. She changes the rules of the game by just existing. If you're higher health than her well you may still be losing. She has true damage, crowd control, sustain, wave clear (and can farm under tower), a gap closer, free crowd control reduction, a wide assortment of build options and is just plain silly. She's one of those characters that has been nerfed so many times that she even has a meme. Sure it's gotten to the point where she isn't as obscene as she used to be but she can still potentially have those moments of being outright stupid - aka the ionic spark build.
In short - toxic design just ends up being near impossible to balance perfectly. Adding or changing anything to the champion or the game as a whole can potentially erupt their power to levels of ridiculous or pathetic.
So why is it important to know these three balance things? Well for starters - you can stop saying some of the dumbest arguments ever on the forums. It is almost unfair that people who don't fully understand balance are trying to tell Riot how to balance the game. I'm pretty sure they know what they're doing and for the most part they simply want to be careful not to overdo it sometimes. Even when a character has been neutered by nerfs - it doesn't necessarily mean they're out of the game (Rengar, Irelia, Jarvan).
Think about whether a character is legitimately overpowered or if they are just annoying to play against. Then if they are annoying think whether or not that actually justifies a nerf. In most cases it doesn't.