Well then would you rather it function like a stun where it instantly puts you into a CC'd state? Given that she would then be able to instantly combo that off various usages of RQEQ for maximum damage from the Q distance and E double down sleep disruption damage I personally like that there is a semi long delay to give you opportunity's to position. If her Q is already out cuz shes going for a long range nuke the delay can give you time to set up a minion block or have a teammate hero and tank the hit for you, or potential get out of her range. If her E was like say a morgana Q I really think it would make her to strong.
Like I said, know the mechanics and adjust your thinking. You got to treat it like a morg Q, not like say zill Q.