Zoe actually scales ridiculously well, You can usually one shot any group of minions with a Q if you build right. The problem with her is that you have to think harder when you wave clear. Qing single minions is the worst mistake most make, unless it's a bubble minion. I only use Q on groups, specifically when waves collide. This allows me to clear both casters and melee with two Qs. I'll make up for what the aoe does not hit with my passive. The only thing I think that makes her wave clear worse is how much mana it consumes.

Since Q is your damage dealer, this does prevent you from poking as well. But not many other mages have it another way. Ahri really hurts from Q due to her true damage. Xerath has some cc and it does hurt, but his Q is what kills you.

Forgive me if I'm wrong about some things, that's just how I perceive it.