Riot just can't prevent broken champions can they?
Fizz, Zed and Twitch are obviously broken, Fizz has the easiest escape in the game, unlike Yasuo he it is invulnerability AND like a flash. THAT is a broken design. I play Vel´Koz, what does he have? Sure he has true damage but you need to hit all skillshots to proc that and that is NOT easy.
Look my point is in all honesty, champions are just too unbalanced, their designs are just too OP. Sure a really good player can most likely stomp a average Fizz but that's not the point, it's just how much damage and or utility they have in their package.