Okay, here's what I've got.
In order to accommodate the vastly increased cost for full physical Immunity, I raised the cost of the various broad physical Immunities.
The costs now increase a bit more smoothly, and I think Tedronai's issue has been addressed.
We done?
IMMUNITY [-varies]
Description: You are completely immune to some form of harm.
Note: The cost examples provided here are intended for the hypothetical average game. In unusual games, they may need to be adjusted. For example, he costs here assume that effects like All Creatures Are Equal Before God are supremely uncommon; if this is not true in your game, the more powerful variants of this Power might well be overcosted. Alternately, an an anti-anti-defensive-Power Power could be added to the game. Said more powerful variants are likely inappropriate for some games and should be used with caution. In some rare cases, it may qualify as a Compel when this Power does not apply. Effects that reduce Toughness by one level reduce Immunity to Mythic Toughness.
Skills Affected: Many.
Effects:Immunity. Pick a type of stress. You are immune to that type of stress. This may prevent certain maneuvers and blocks from functioning, at the GM's discretion.
Variable Cost. The cost of this Power depends on the type of stress selected.
- Completely trivial immunities, like drunk-ness or bad smells, are free.
- Very narrow ones, like monkey wrenches or seduction attempts or falling damage, cost 1 Refresh.
- Narrow immunities like poison or acid or magically induced despair cost 2 Refresh.
- Immunity to a single common thing, like metal weaponry or explosions or fear, costs 3 Refresh.
- Immunity to a broad group of things, like the physical attacks of the undead or mental magic, costs 4 Refresh.
- Immunity to an extremely broad group of things, like all magic (including indirect spells) or all unarmed attacks, costs 5 Refresh.
- Immunity to all mental stress with a sizeable weakness, like the attacks of women, costs 6 Refresh.
- Immunity to all physical stress with a sizeable weakness, like cold iron, costs 7 Refresh.
- Immunity to all mental stress with a small loophole, like the attacks of genderless beings, costs 8 Refresh.
- Immunity to all mental stress costs 10 Refresh.
- Immunity to all physical stress with a moderate weakness, like holy stuff, costs 12 Refresh.
- Immunity to all physical stress with a small weakness, like a single legendary weapon, costs 17 Refresh.
- Immunity to all physical stress costs 22 Refresh.
- Immunity to all mental and physical stress costs 30 Refresh.