I really don't know what I'd do to make flare star feel good.
The only thing I could think of is making it maybe an oGCD when used in leylines or something if that's possible. Idk if even making it an instant cast or oGCD would even add much, it would just be a movement tool or if it did enough damage something you use to end despair. Honestly feels like they should of just made flare star an instant cast after despair because that feels like the only point youre supposed to use it, using it outside of that feels awkward.