This is an issue regarding champion balance that actually has grave consequences both in and outside the game.
Eve
To take my latest game as an example, I felt like playing Eve, I have played quite a bit of Eve during my time in LoL. Before she was considered OP, when she was OP and until you made her really bad by removing her stun.
The result? Within 3 minutes of the game, my top, mid and jungle were AFK, I had to endure flaming for close to 20 minutes and I got reports from 3 in my team, and atleast 2 on the other teams.
Let me say that again, I picked a champion, I played it seriously (roaming), 3 people went AFK, flamed me and then I got atleast 5 reports for picking a champion I wanted to play. And this was at 1650-1800 elo.
I have over 2500 ranked games played. I have one ban during this time, and I'm strongly suspecting that ban was from playing Eve, and getting 8-9 reports for it even though I had better stats than 2 on my team and I did nothing against the rules.
Either you balance Eve or you disable her. People are getting harassed, trashed and banned for playing a champion which is UNACCEPTABLE