What is Zoe's Sleep Drawback exactly?

it make u sleepy u fall asleep hwen using it ;O

It can be wasted by an untimely attack. If Zoe lands her sleep, and youre immediately hit after then the sleep never really works.

It takes a while to activate o.o

It moves decently slow and the range isnt impressive. The real draw back to zoes kit is the fact that her Q and her E are the only source of reliable damage she has. She has to spend a summoner (a costly thing) or get a shard from a balloon, which is risky because she has to risk being out of position just to get it. So if it isnt flash, shes kinda fucked.

It immediately wears off after the target takes damage, so that's a thing.

It's not broken enought?