I think in general there are too few good healers, not only in fire element, and some too op ones that shouldn't exist (like sailor sakura and hokage tsunade). The game is too unbalanced towards damage. What misses currently are healers that also shields or grants higher damage reduction effects (like kurenai, but also by standard attack), healers that buff defense/resistance of the target and healers that add a regeneration effect (something that works like leaching, but as a set thing at the beginning of the round or before a ninja standard attack).