A movespeed buff on her would help her weave in and out of the team fights and apply her buffs more effectively. I know it's not in original core gameplay, but giving her a higher base speed than Pantheon would make her quite interesting to play as.
It would also open up an option beyond AP tank vs AP. You could forgo boots early on in favor of better trading power. Similar to how Fizz, Karma, and Pantheon are often played.