I'm going to try to keep this short.
Obviously, we can't have an actual healing ability that simply works on a cooldown. Were that the case, it would be far too easy to simply stay put and wait to heal everyone to full, then keep going. That's kind of game-breaking. Instead, here's two ideas as to how Battle Sprites could add (what I feel is a fairly balanced) healing to the game. Tear them/me apart at your leisure, I just ask that you actually read the whole post first.
Ability1: Vita-Nom(?)
You know how you get all those extra Vitapods after everyone already has them? Totally useless. Slightly annoying. This ability would give you a couple seconds to pick some up, and re-drop them as a fraction of hearts. Example: You activate the ability. For the next 5 seconds, any Vitapods you walk over, instead of being picked up, explode into hearts. You pick up a 9-Vitapod, it turns into 3 hearts. Has a five or more minute cooldown.
Ability2: Healing Finish(?)
What this is is a fairly weak attack launched by your sprite. It does about as much damage as a normal attack from a gun at whatever depth you're at. If you just use it willy-nilly, it's just an attack, no side effects. However. Should it be the last blow that defeats an enemy, that enemy is *guaranteed* to drop hearts when it dies. The number of hearts is relative to the amount of total HP the enemy has. A Lumerer finished with this will drop more hearts than, say, a Devilite. Obviously this only applies to enemies that actually drop hearts, and not things like Royal Jelly Minis. Other enemies with very low HP, like I assume mobbing type enemies like Dust Bunnies will have, will also not drop hearts.
(Note that this ability is SLIGHTLY ruined by the addition of health bars in the new UI)
What both of these abilities do is force you to keep fighting. You can't just sit back and wait to heal up. Instead it just gives you a better chance at getting heart pick-ups.
And yes, I know the names are retarded. Feel free to post any suggestions for better names.
Ability 1 seems like it should be a passive ability, since there's no time you wouldn't want it on. Ability two seems like it should be a "mark" ability where the target has a mark on it for a few seconds (maybe 10) and they 100% drop hearts if killed in that time.
Also, these should probably both be for Seraphynx only.