I'm kinda in between these two comments.
I agree that her new kit is great. She's much more effective and interactive than before. She has amazing poke and her E is very useful.
However, I also agree that she has an issue with survivability. Soraka is slow, very slow unless her passive is active, and she has to sacrifice health to heal. Landing Q is a MUST to keep up the healing, but doing both in a fight is difficult. Soraka is very squishy, meaning you pretty much HAVE to build her tank. Building AP just isn't gonna work out because she's so squishy and WILL be killed in fights because she's a priority target.
Other caster-type supports don't have to make the sacrifice Soraka does. That's the biggest issue, in my opinion. I think there can be a happy medium between having power and survivability.