It would be great if priests could walk around when they are not busy with creating units and heal other units automatically.
This feature might be achieved by finishing an extra upgrade for example.
To be honest, I have never used manual healing - I just did not have a time for that.
PS: I do not know if units belonging to other factions do have this healing feature too (probably Tech has a Technician for this purpose as far as I know), so it would be good to make this upgrade available for them too.