Reign of Gaming

Well, I unlocked Diana and I played her alot this weekend, imo she is god tier. But I havent really found a perfect item build yet, can someone help?

There is no doubt Diana is god tier AP. 

Problems with Diana (I love playing her) on TT is that she's an assassin. Normally teams are tank/AP or bruiser. If she can snowball early game she has a chance, but if not she just can't kill easily. Sure she has burst, but after that she has nothing, and most 3v3 champs can withstand her initial burst. However she is good if the enemy team has an ADC, or a squishy comp.

Just wondering, how come Blitz is Tier 4?

might want to put Mundo in lower Tier 1.
Hatchet is cheap and counters him hard, along with Ignite and Morellos.

Agreed - a lot of things really counter Mundo and there's nothing about the map that really makes him extra extra good. Apart from the tank meta being good for his Q

Cho'gath isn't just a great AP... Wit's end + situational resistance items is giving me a 90%+ winrate from top lane right now.

Cho'Gath is a great jungler too, fast clear, very strong ganks just a really great pick on TT & SR in general. 

His Q can be hard to land if they are really mobile but otherwise as long as your a little patient and wait for them to commit to either an escape route or who they're trying to focus it's pretty easy to land. 

+ You can always gank from a bush for monsta ninja ganks. I think Cho'Gath Q isn't anywhere near as difficult to land as some abilities since Riot shortened the delay. 

I personally feel that Vayne is placed too low - i find her to be easily Tier 1 - here's why:

With the tanky meta (Darius, All of God Tier, etc.) her passive gets a change to go absolutely mental. Build some AS and you rip through the tanky beasts like butter. She also has a good escape AND to quote my brother who mains Vayne and played his first 3v3 a few days ago: "it seems like no matter where I am or they are.. there's a wall to stun them with. EVERY time.)

And then I also feel that Kayle is a more significant threat than Jax is - I would've switched their places in the list, but I may be alone here. I haven't won many games against Kayle, but I keep winning against Jax. I don't have any logical reasoning here, though - It's just a gut feeling.

Thanks for the list! been awaiting it for a long time! :) keep up the fantastic work!

Most ADC's are BROKEN on Twisted Treeline honestly your going in the right direction but despite big damage output isn't as safe as Cork or Vayne (I know you did mention her but I don't think you recognise this point) & Ez etc. Your probably thinking because people will focus your ADC and burst him quickly, that's actually not usually a problem assuming you have a Cho'Gath or a similar amount of disruption (which I think is pretty key in teamcomps anyway) and you can position yourself correctly by the time a champion reachs your ADC at the back of a team fight they will be low and he can just burst them down (Autoattacks hurt). 

One of the reasons ADC's are so strong is because of their ability to completely clean up a won teamfight, high mobility combined with long range. Unfortunately Kayle's range is limited to a timelimit & her movespeed buff isn't long enough to chase down flashes or similar blink abilities.