Yeah, I think her Q spell needs a buff, more than anything.
Right now I'm finding the best way to play her is to concentrate on her burst damage by going the AP route, and that leaves her Q woefully weak.
She doesn't really benefit much from DPS items as she's pretty weak in a straight out 1v1 fight - she's better played as a finisher/chaser/sniper in team battles.
Plus the W + Q combo is nowhere near as useful as her W + E combo, even if you go the DPS route. Healing Reduction is practically useless.
Edit: Also I agree with EternalOne about her not getting a stun or slow. She can already get those via Exhaust/Rylai's Scepter/Frozen Mallet, can already chase very well with Shunpo, and her not having a reliable snare early on makes her more reliant on teamwork - which is always a good thing.