Well I think I'd prefer freform.
As for my starfire idea, her powers are more technical and slightly higher level, the same way Ultimate versions of existing characters are, but her biggest difference is that this version is a nudist. She needs sunlight to recharge her powers, she can survive in any environment, and her culture just doesn't have any nudity taboos.
If somebody asks her to cover up, she'll passive aggressively ignore them, after all normal people can't exactly tell her what to do, and most superheroes don't think it's worth getting into a fight with an alien warrior princess over.
It also helps that her body emits light, which de-emphisizes her naughty bits, so most people let it go.
Differences in powers wise, Aside from the standard flight, super-strength, and invulnerability, she has control over all forms of solar radiation, She can see the entire spectrum, shoot lasers, make a thermonuclear explosion centered on herself (She rarely does this because it drains all her power and causes considerable collateral damage), and possibly if you allow it, turn herself into photons to fly at exactly the speed of light.
Personality wise she'd be a slightly more mature version of the Animated Starfire, rather than the bland personality of new52's slutfire, but she would be just as promiscuous as the latter.