First you need someone good to play an OP character. I Can play someone like 
and still suck while other people get 30-1 with her.
Especially nerfing some champs to much. For example, why did 
need to get nerfed? Barley anyone plays her and isn't OP at all.
Don't even get me started with other games like Destiny either.
-5 keep em coming
Well let's see LeBlanc before she had her silence taken away had 0 counterplay once she landed a single point and click spell. She would just Q then combo in and you could not react at all to her. It was the same thing with Kassadin before his silence was removed. Vayne I don't remember being nerfed anytime recently, plus she is a late-game adc that you need to shut down hard in the early game to keep her from snowballing out of control. As for Ahri the only real "nerf" she received was when they took away the bonus damage modifier on her charm because it was making her a very linear champion that if she didn't hit that one spell then her attack pattern could effectively be ignored. Nerfs do not ruin games they simply open up opportunities to exploit champions in ways that you could not before, otherwise you will always see the same 10 champions in every game because they truly are ban or pick.
LCS plays quite a number of champions between the EU and NA splits not to mention what they play in LPL and LCK as well. The pool is not as tiny as you might think. While there are definitely a few highly contested champions like Kalista, Rumble, etc... the pros play a wide variety of the champs that are available in this game.
Please try again.
Ahri's still among the best mid laners in the game though. Her damage is great, she's very mobile, and a good charm can spell death for most. Barring AP Ezreal, she's actually the most picked mid laner in the game right now (assuming the majority of Morgana and Annie picks are in the support position).
