I would not say that Healing incantations are the problem, but it's more the ability to cast stuff like Regrowth Belt and lots of armor bits off a Battleforge multiple times that can be problematic. That kind of play, unlike playing a more powerful healing incantation, doesn't constitute losing tempo because you're not actually spending an action, yet the only way so far to stop that is for the opposing mage to spend in action either on a Dissolve, Poisoned Blood or Deathlock. You could attempt to destroy the Forge, but that's further resources not spent against a Mage.
You combine this with the Wizard's Voltaric Shield, and it starts becoming a real issue. At that point, the Wizard is really only limited by mana, not actions, and the Wizard is the best channeler in the game so actual game time limits and rules become a real concern.
There are effective plays vs this kind of stall play, like curses and cutting healing, but the fact remains that when you start combining all of those free actions off of a Battleforge, Hand of Bim-Shalla (which should be Holy-Mage only, honestly, it would have solved the situation a long time ago) and the Wizard Tower, other mages simply cannot stand up to the sheer amount of free stuff the Wizard has access to after a while.
That's why the focus needs to be on actually dealing damage, because otherwise games lose direction. The other thing is that when you give access to all of these conjurations and things that give free actions, it doesn't take a genius to figure out how ridiculous that can get when you combine all of them. That heavily tips the late-game favor to the Wizard, who at the moment has unparalled access to free things, and abilities to ensure that, unless a time limit is properly enforced, he will get there.
So, if I were to change things, I would:
1. Make Hand of Bim-Shalla a Holy Mage Only card, because while it's not great at first, the sheer amount of free actions you get over the course of the game should be limited to mages which do not already have stuff like the Wizard Tower
2. Make it more favorable to interact with equipment and the Battleforge. Right now, a Battleforge is just way, way too safe of a play. I see no reason why there cannot be a Purge Magic equivalent for destroying equipment, especially when the Battleforge is available to all mages.
3. Emphasize damage as the way to determine a winner. This isn't Heal Wars.