I understand that it's really strong, hell, it has really freaking strong scaling on it when used right, the main problem is, though, at what point in my playstyle with any eni build will it flow well with the other spells I'll use?
Healer Eni? Definitely wont use flaming stacks
Damage Eni? It's not the most reliable option, plus the other damage spells would warrant more wanted focus
Buff/Debuff Eni? You could use it, but there are just more spells that fit the overall desire of most builds
I even run around with a tank that uses Flaming, but I still wouldnt intend on using it with him. It's just an awkward spell that doesnt flow well imo.