what champs are overpowered?

All of them. Except the one you're playing.

Only one is overpowered. .

Most bullshit champ in the game by far.

Overpowered. Azir, Illaoi, Brand off the top of my head.

I can give my reasoning for Illaoi and Brand right now.

Illaoi: Extremely high base stats, to much damage on her tentacles. really just remove some of that damage and she would be alright. Brand: He's got a really strong kit sure, but honestly if you were to tweak the range on his Pillar of flame, or make the delay longer at more distance, he would be fine.

I also Think Yasuo, Blitz and anyone that counter Annie is broken. but people complain if i say they are overpowered

is now one of the strongest champions in the game. His isolation damage got buffed and his jungle clear is absolutely insane since red and blue camps are now single monsters. Dueling him solo is almost impossible.

inb4 everyone cries "Yasuo", because ya' know, just Boards shit.

Rengar and Sona

All of em

Depends how you define overpowered. The way I look at it, a champion is "overpowered" if one of the following is true: (note that I put overpowered in quotes because I don't actually personally believe they're overpowered, just moreso that they're incredibly frustrating to play against or in general are more "unfun" for the enemy than they are "fun" for the player - skip to the last paragraph if you're planning to just downvote me please).

• They get a guaranteed won laning phase: this basically means as their opponent the best you can do is go relatively even, so if your teammates are losing you lose the game. An individual having no control like this is really unfair to that player, since you should have some say over whether your team wins in any game. all seem to fall in to this category to various extents (that extent largely being how many champions can beat them at the role, the fact that junglers aren't nearly as oppressive as laners, etc...). Pantheon is probably the worst culprit of this.

• They can't be punished for their mistakes (or worse can prevent allies being punished for their mistakes). Basically, the typical mobility complaints - when a champion has an otherwise strong kit and has mobility thrown on top of it - although this also applies to champions who simply scale really hard despite losing a game hard early, or champions who are just nearly impossible to kill even when way over extended. all could arguably be placed here to various degrees.

• They have a gimmick that really ruins the game for another player. All ranged top laners, may express this to various degrees.

• They're actually OP. Which currently, no one is. Like really, the game is fairly balanced right now. The above could all be argued "OP" but I've really covered about 1/4 - 1/3 of the champion pool. There's a lot that make champions unfun to play against and players dread seeing them regardless of whether they're really strong or not. That's probably not really healthy for the game and if it makes people think the champion is OP that's a reasonable response. Really though, maybe 1 or 2 champions becomes OP every few patches but for the most part this game is balanced quite well for how many champions there are available.

vayne, rengar, khazix, syndra, lb - these are in a need of nerfs