I'm not sure if anyone feels the same way, but I strongly believe the mage's ability to heal other units is way too expensive to be worth it. It costs 300 to heal your units by 1 hit point, whereas 300 would easily reinforce most units to full health at a nearby captured village. I would like to propose reducing the cost of the Mage unit's ability to heal proportional to the amount of hit points it can increase, or increase the amount of healing a Mage can do for the cost. Even if it's not for full health, if you were to raise the HP to maybe 3 instead of 1, that might be sufficient. I hope you can take this into consideration and possibly implement it in the future patches to come.