I had on mind writing a longer commentary on why all new champions are good the way they are (in contrast to the screaming and yelling "NEW CHAMPION OP"-crowd, that is).
But you know what? The Guys from Extra-Credits did that for me today!
This video explains the entire balance system of games (they use League of Legends as example several times and they in-depth explain how LOL balance system works at 4:15).
Feel free to link anybody here who cries about the new champion.