Does anyone other than me find this power largely inappropriate in the game?
For example, let's say I'm designing some kind of a BBEG. I want for him to be extremely badass, tougher than even Mythic Toughness. Because of God-mode, there just isn't any place for designing any other super-Toughness powers. Why even bother? God-mode is available. I can't ever have a Toughness power cost more than -7 Refresh because -8 is invulnerable.
To every Toughness power there is a catch, especially for Physical Immunity. In the case of a BBEG it might be the one thing that is able to kill or disable him, and that is ok inside of a story, as long as the players have an interesting way to get it. The story is going to become less centred around fighting the BBEG and more centred around the quest for finding that one thing that can defeat him. Or the PCs can only foil BBEGs plans, but he lives to fight another day. After all, that is all Harry is able to do with Nicodemus so far.
It's also placed in some highly unsatisfying places in the book. For example, Ogres have Physical Immunity to magic. I mean, does that seriously mean that an Ogre could basically walk into a meeting of the entire White Council and the thousand or so wizards could unload enough magic to level a city and he'd just shrug it off? GM Fiat here is not really a satisfying solution.
Sure - I can get that Ogres are very tough against magic. But they're also nowhere near heavyweights, they shouldn't get to laugh in the face of the entire Council if they unleash their full power.
If they are throwing their magic directly at the ogre, then yes, he is going to smash his way through them. But as others pointed out, wizards have lots of different ways to use their magic other than point and shoot.
Similarly, some other creatures I don't think deserve Physical Immunity. Sure, the Loup-Garou is badass. Sure, it could rip apart an entire police department. So, can it survive a nuke? Ten? Fifty? The full might of Queen Mab if she doesn't use some sort of a Catch-satisfying ability?
Yes, it could. And it is not completely immune to anything, it can be hurt, even killed by inherited silver, it's catch. Queen Mab would be able to bind it, as would possibly a nuke if it buried it under a few thousand tons of dirt, but it would not be killed outright. And don't forget, a Loup-Garou is only a Loup-Garou for 3 days of a month, so if you want to do something to it, there is plenty of time to do it.
Again, GM Fiat is not a good solution. As a GM, I can already do anything. The rules in the book are there to tell me what I should and should not do.
So, opinions on this? If you share my opinion, did anyone come up with some sort of a custom power for other high-end Toughness abilities?
As I said, it all comes down to the catch, and that is something that the book tells you. I don't really see the need for any other high end toughness powers. Anything other than mystic toughness would make you immune to battlefield weapons, so putting up a physical immunity at that point is more than justified.
If a player absolutely wants to take up physical immunity, make him pay (by compelling him on his catch). I had a shadowrun player once, that wanted to take an allergy to gold on his character to gather up some more creation points. Too bad, that most cyberware connectors are made of gold...
What I'm trying to say is: if a character wants to have physical immunity, there is going to be something else, that is going to get him. Maybe his catch, maybe the BBEG goes after his loved ones instead of him. The character is going to think twice before storming the castle, if his friends are in the line of fire.
And for the most part, if I read it correctly, Physical Immunity is used to get Immunity for 1 condition instead of all but 1 thing, which makes it far less powerful, but gives a nice touch to a creature. A fire elemental's immunity to fire for example. Or - as you pointed out - an ogres immunity to mortal magic. And as far as I understood that, only the older and tougher ogres would develop the strength to shake of mortal magic like it was nothing.