Her burst is bad but being able to get a 3 sec CD on her Q I suspect they want you to play her as a poke mage. Problem is others can do it better and safer. Her R is the problem as It should make her abilities at least as powerful as a normal ultimate but none of them are as good as most other heroes. I defended her when she came out as the numbers on her kit misled me to it being good. 1.5 total on her Q when Mantra'd sounds awsome, but its a skill shot with a small radius and low range for ultimate that people walk out of the last 1/3 of the damage anyway. Plus that is 2 abilities used for you to achive that ratio.
She is not worse than before but I don't think she is better either.
Her damage is pretty strong, but as said she has no real burst - just pokes. The closest burst you can get is using the W tether, and dropping a mantra'd Q just before they get snared so they can't escape its 2nd activation. With Ignite thrown in there, and after a bit of poking. She should never be played as a support in my opinion (the fact that sightstone is one of her top items on LoLking leads me to believe this may be partially why she was a poor win rate). She is pretty under-rated.
I understand that Riot took away her sustain so that they could give her more power. But she isn't anything special as a support without that heal. She makes for a decent mage, but few champions can take advantage of her constant pressure.
So essentially, she works better in general, but she doesn't excel at anything to warrant picking.