Well how could this possibly end badly....

" Fizz Fizz has a pretty unique role: he’s one of the few assassins who can initiate on his own, and we wanted to accentuate that. We’re also giving him more room to play around his slippery mobility, so that - above all assassins - Fizz is the hardest to pin down and peel."

So unless this is accompanied by significant damage nerfs he's just going to spew feelsbad all over the rift.