In my opinion it's just Fizz's E that makes him so frustating.

I think we all can agree that playful/trickster is one of the best escape abilities in the game. What I don't like is how it can be used offensively well, and how it's cooldown is low. Look at Vladimir or Yasuo for example(neither of them needs buffs, just example). Yasuo has a wall blocking incoming projectiles for a duration, sure it is strong but Yasuo can still be catched. Vladimir's pool barely deals any damage and is used for escaping/waiting your ult heal to come in and stuff like that. Both of them have the abilities on higher cooldown than Fizz's E and they aren't even used for offense. Meanwhile Fizz can either escape or use it for offense. Lategame a Fizz will have just a 10 second cd on it, but he will for sure have some cdr a bit so it will be even smaller. Just do something with his stupid E... anything. Fizz becomes a hell right after hitting level 6. If he hits you with your ult, you are basically exhausted and knocked up after. Not to mention how while the fish is on you with the slow, you cannot trade Fizz becaues then he simply will E and you miss all your stuff. Fizz is just so frustating to play against. Christ... I'd even rather have a Shaco on the enemy team than this champion.