Are Assassins Overrated?

I mean, Zed and Kha'Zix were two of the biggest picks in worlds but both were just a giant BLEGH coming from either side. Neither made any noteworthy 'plays' and exhaust/peels made them mostly worthless, or in Kha's case just a supportive slow/poke champ that didn't have any solo kill potential on anybody.

Fizz is arguably very strong when ahead but he didn't do much even in the hands of Pawn.

And look at Solo Q where Most Zed, Kha, Lee, Fizz don't really manage to do anything much but guys like Katarina can really destroy entire teams as an exception.