Today i am bringing you an ARAM aram tierlist made by Reign of Gaming's forum mod Bystekhilcar. He goes into great detail about his placements, so belt up guys, this is going to be a long one.
Tier 2 :
Amumu, Anivia, Ashe, Cho'gath, Galio, Heimerdinger, Janna, Jarvan IV, Karthus, Katarina, Kayle, Kha'zix, Leona, Malphite,Malzahar, Maokai, Master Yi, Miss Fortune, Morgana, Nunu, Poppy, Ryze, Taric, Thresh, Tristana, Twisted Fate, Twitch, Varus, Veigar,Viktor, Xerath, Ziggs, Zyra
Tier 3 :
Ahri, Alistar, Annie, Brand, Cassiopeia, Corki, Darius, Diana, Dr. Mundo, Draven, Elise, Fiddlesticks, Garen, Gragas, Graves,Hecarim, Jax,Karma, Kassadin, Kennen, LeBlanc, Lissandra, Lulu, Mordekaiser, Nami, Nautilus, Orianna, Quinn, Rammus, Renekton,Riven, Rumble, Sejuani, Singed, Sivir, Soraka, Syndra, Talon, Teemo, Urgot, Vayne, Vi, Vladimir, Wukong, Xin Zhao, Yorick, Zac, Zed,Zilean
Blitzcrank : Grabs change the game. These give constant threat of free kills, irrespective of the state of the game; unlike other grabs, this one is clean and puts Blitz in no particular danger. Naturally beefy due to his passive, and has the option of building bruiser or burst AP as required.
Caitlyn : Obscene range coupled with ADC scaling AND strong poke. Traps can also make for easy bush kills. The single best ADC in ARAM by a wide margin.
Ezreal : Possibly a controversial choice. Nevertheless, extremely versatile champion due to his ability to build AD or AP and be extremely strong as either (if built properly). As AD, extremely mobile and brings very heavy poke; teamfight-winning ultimate. As AP he would probably be T2 (but close to T1), bringing obscenely good poke coupled with strong AoE.
Jayce : Very strong poke, albeit on relatively long cooldown. What tips him into T1 is his extremely high burst potential through form switch, coupled with the disengage and repositioning power of his gate. On the cusp of T2 due to limited utility and poke, but just edges in.
Kog'maw : Similarly to Ezreal, he can be built AD or AP depending on the needs of the team and his opponents, and is extremely strong in each. As AP, his poke starts off mediocre and builds up to be game-winning as the game progresses; he also brings deceptively strong burst. As AD, he's again better suited to later in the game, but can then provide fantasic range along with ridiculous DPS.
Lux : It may surprise many of you that Lux only just made T1. Her poke, although strong, is actually somewhat weaker than the rest of T1 (assuming the two variables are AP and that Blitz's grab is basically an instakill). Her shield is also pretty limited due to its travel time. What tips her into T1 is the combination of strong poke and the fact that her Q can set up her teammates' pokes as well; this provides exceptional utility.
Nidalee : Pretty much defines Tier 1 as you'd expect. Incredible poke, along with bush control and sustain. If you're wondering why a champion in Tier 2 isn't in Tier 1, it's because they're not on Nid's level, pure and simple.
Sona : Great sustain and strong ultimate. Her Q's range is mediocre and her power chord very limited, but where they're safe to be landed they're effective at bolstering an already effective kit. Her auras also offer a signficant gold pseudo-advantage. Has some issues surrounding her natural squishiness, but not enough to be a liability unless played badly. Note : Was originally T2, moved after discussion (and a hefty bribe from A2).
Tier 1 : These champions are ones you'll only get if you're particularly lucky. They are perfectly suited to the ARAM environment, and if played well enough can effectively carry games alone. Please note that many champions which people view as extremely strong in ARAM are not quite at this level; look for them in Tier 2, and don't complain too loudly. Tier 1 is reserved for the 'best of the best'.
Tier 2 : Very strong pickups. These champions are typically very well suited to ARAM, but lack a certain something which allows them to carry games effectively. Often they're T1 material if not for a single factor.
Tier 3 : Decent champions. You usually won't want to reroll these, although you may trade them away if another champion suits your style more. Their defining feature is typically being strong champions in and of themselves, but being unsuited to ARAM for one reason or another. The majority of champions fall into this bracket.
Tier 4 : These champions have the potential to be a decent team member, but struggle due to various aspects of their kit. These are not necessarily 'trash' picks, but will take some work and a good team to be effective. Potential reroll, particularly if you dislike them.
Tier 5 : These champions are extremely unsuitable for ARAM for one reason or another. They are still workable as a team member, but will struggle unless supported very well. Expect to reroll these frequently.
Note that Tiers 1, 4 and 5 are intentionally small compared to Tiers 2 and 3. This is to reflect the fact that ARAM is generally a pretty balanced place, as unlike Rift (which is predominantly one-on-one or two-on-two for a large part of the game) you'll generally not be far from the rest of the players. As such, a champion really has to impress (or suck) in one area to stand out.
AP Tristana : Yes, it's as bad as I said above. For some reason almost every Tristana I see in ARAM builds her AP, and I never understand why – I'm aware that ARAM is meant to be a bit of light-hearted fun, but I fail to see what's so fun about being useless all game. She has a completely redundant Q, a W which is a great escape and would be a great damaging spell if it wasn't suicide to use, a very limited E (poor initial range with great rank 1 damage; later on, good range with poor damage. DoTs are also weaker in ARAM due to the proliferation of Barrier). Oh, and her ult deals a lot of damage with AP – but if you misjudge it, you're almost certainly going to mess up your team's positioning and give the target a free escape. Essentially, you have one non-ult damaging spell and a half-decent ult, both of which are single-target. As opposed to an ADC (which are generally strong in ARAM) with a fantastic steroid and scaling range. I just don't understand.
Glass cannon Karthus : Similar to the above, I don't understand. Yeah, great, your ult hits about 20% harder than it would otherwise; in exchange you die instantly in every teamfight and don't actually do anything except press R every few minutes. And even then you don't, because you want to save it for when you think you'll get a kill with it. Then you don't (because Barrier), making the entire exercise fundamentally pointless. Really... why would you waste a decent champion for the sake of a tiny amount of extra AP?