Wow, you didn't even look at the nerfs before speaking. What a genius
So just to wrap up the final stupidity of your points:
You know why he has that passive?
Ranged harass
Ranged harass
Ranged harass
Ranged harass
Ranged harass.
Look at any other midlane, any one of them, and you'll find that every one of them has a form of ranged harass to get an enemy low enough to go all-in. Fizz requires that passive because he can only go all-in - he doesn't get another form of harass, he doesn't get "poke", he doesn't get a shield or sustain or anything else - he gets a bunch of abilities that require him to bury his face in the other laner or do nothing. If he didn't have that passive for his laning phase, he'd be garbage.
And he doesn't "dominate" all tier levels - he does moderately well most of the times with some moments where he finds himself doing well. Why? Probably because before this upcoming patch he was able to build whatever he needed to to fit his team rather than fill his designated role. Welcome to logic. Now he's fixed. Next time look shit up and think before you spout off.