Since Riot has mentioned they want to remake her I am curious what people would like to see. Think of all the new tech in the game and what can be done with her to make her a dedicated healer that is interesting.
For me, I want to see he as a protective, reactive healer. A few ability mechanic/ability ideas:
Soraka charges up a celestial bolt, gaining range as she charges. This bolt only hits champions and passes through allies.
Hitting an ally with the bolt heals them for X(+AP).
Hitting an enemy with the bolt deals X(+AP), slowing them for Y(+AP) 1.5 seconds and knocking them back slightly.
(Skillshot healing and soft CC. Can hit multiple allies, or hit an ally and knock an enemy back. Good life saver.)
Soraka shields target ally for X(+AP)(+MissingHP). Damage dealt to the shield heals the target for the same amount (up to X(+AP)(+MissingHP)).
(Combat healing. Can be stronger than healing alone. Outside of combat you get NO healing as you take no damage. In combat you get the shield, plus the shield again in permanent hp if they remove it. Great in combat, unable to sustain.)
All I have for now. Interested to hear other ideas. :P
Maybe more interesting ult ideas. I know they want to move away from global stuff. Think of all the possibilities O.o