I have started using the healer once more and really enjoying the no air trap benefits.
However, last night when the giants came under fire I immediately sent out the healer. Instead of going to the giants she started healing 5 archers I deployed on the perimeter to take out the outbuildings and therefore had full health. She continued healing them until they closed in on the base and immediately got taken out by mortars.
I got a summary about clash of clans healer deployment from this experience:
1. The healers go and start healing a rogue group who are at full health or are small troops and were going to die anyway. The best way to fix this is to change healers from splash damage to multi target so she will end up being more centralized to maximize her healing effect.
2. The healer is better appropriate to heal giants in clash of clans for bigger damage. Therefore, deploy healers near to giants.