I have a GREAT idea regarding healers!
Pretty sure you've seen this great idea suggested before, but how about making your healers, how I say, acting as if she's not a cold blooded and callous social worker that doesn't even care about the work she performs, nor that she has any visions despite the point of view advantage.
Often times, I think she is guided by the cries of pain and every now and then tosses out a mercy heal, indiscriminate, uncaring, and unpredictable. Perhaps she's guided by another force - bribery from that one archer - so she'd concentrate on that lone archer and make sure it is the last unit standing. Ex lover?
Perhaps that archer is also a government worker? Now that I think of it, that seems to fit the mold as I often see a few of them just shooting at the walls, pretending that they're doing something while their comrades are dying next to them...
Or, it could be that the archer just have really good health insurance, one that I haven't seen. Probably either a politician's offspring or a .001% of the population. Either way, it makes me a bit sad.
Please, please have a word with your healers and perhaps get her to be a bit less prejudice. Giants have feelings too you know.
Serious suggestion: give healers a "priority selection" before deploying, based on the type of troops you're raiding with. I think this could be done on a two-click approach; click one selects the healer, click two "bonds" it with the type of troops you want to give healing priority for that battle. If the prioritized troops die off, then she can go back to being a floating bimbo.