Personally I dont think regen should scale with shards beyond +1 point per turn, at least not in tactical combat. Even a +3 heal every single turn is far too powerful, IMO. Perhaps the shard bonus should only apply outside of combat. I didn't even know about this bug, and already found regen to be an awfully powerful buff for the cost at +1 per turn.
A regen effect should primarily be used to minimize downtime (still a very potent and useful ability), not to give significant free passive combat healing every turn. That's what active Healing magic is for, and it should cost mana. Let's face it, with even an average set of armour, and doge bonus on top, a 5 point heal/damage reduction every turn is going to make you functionally immune to any but the hardest hitters on the map, not to mention support really cheesy kiting tactics.
Or, if you actually want the spell to be that powerful, it should at least have a commensurate cost, and the upkeep should scale with each point bonus you get, so a 5 point regen cost 5 points upkeep.
