Another idea for LotM, albeit an unorthox approach:
Light of the Martyr - Sacrifice your own health to instantly heal an ally to full health. You take damage equal to 50% of the healing done. 6 second cooldown.
Replaces Lay on Hands.
This design would bypass poor tuning and would ensure the spell would be able to effectively move health bars at the cost of giving up Lay on Hands. The 50% backlash would serve to regulate basic usage well enough, but I felt a modest cd might be necessary to prevent the player from being able to spam the spell at no risk during Divine Shield.
I like the level of control the design would give the player, being able to choose whether to play it safe and only use the spell on relatively low risk targets or risk living up to the spell’s namesake by choosing to pull an ally back from the brink of death and then fighting to survive the next few crucial moments.
Another benefit is that this design allows LotM to accomplish everything it needs to do without the need of supporting talents, which would allow the spell to act as a stand alone talent that could be placed unintrusively on the tree for those interested.
I think being placed as a choice node with or as a replacement for Power of the Silver Hand would be ideal. This would also free up 3 talent slots on the right side of the tree for more conventional tools, such as increased damage, reduced mana consumption, or improved Auras.