I don't use healers very often but when I do I quickly remember why I don't. AI. So many times for whatever reason I lay all the troops, take out air ds, healers go in and start healing a mass, and then all of a sudden break off and go to heal my single bk or aq who have just randomly decided to break from the group.
I would think it would be cool if they made the healer not heal one unit with splash, but a select number of troops within range without splash. It would essentially act the exact same way as an inferno tower and heal maybe 4/5/6/7 troops depending on level. It could either heal consecutively with a beam connected to a unit like the inferno, or in waves like it currently does and look like a pulsating star. If a unit is fully healed it stops healing that unit and moves one of its beams on to another.
The AI would be programmed to try to heal the most units possible. I think this would make people use healers a lot more and make them actually useful most of the times rather than some of the time.

