Why is fizz so strong in so many ways?

Fizz has extremely high mobility, high damage, % health damage, and to top it off he has 2 slows and a ranged AOE knockup. But lets put all that aside for a moment and look at JUST the fact that he has an "untargetable" spell for a moment. Lets compare him to other champions with untargetable like vlad or master yi. Vlad and yi both have high damage but neither one has a % health damage and both of them have next to nothing in the way of crowd control. So then why does fizz have 2 slows, high burst, high mobility, and a ranged knockup? Seems legit.