Not all of Ezreal's skins are even, bad, though. The problem with Ezreal skins is that the only one with different particles is a skin that costs $20+ and that's more of just a blue recolor
The thing with Zac is, they can basically take an approach for a skin that is gelatinous or a liquid. They may have some issues dealing with his growth as he gains health, but the ideas are there, and with the talent in Riot's design team, they should be able to come up with something.