So to put it simply, i've WASTED my stats all along getting my armor, warding and focus above 75 when i could had been dumping those stats and equipment ELSEWHERE?...yet another reason to agree with people saying the rpg combat system in this game is bullshit.
Well, on the + side, sounds like you don't have to care about actual armor specs with anything your character wears. You could focus entirely on other things with them (Leadership, offence stats, resistances you can't actually get as high as 75 in this game). I never wear my Helm of Heroes for armor, just to make my summons worth a shit at all when I would actually need them and lessen Evasion when I see a power I want to plagurize with Mirror Stance. I always suspected that while Focus can't defend against Mentality attacks past 75, it might help with other things, so between that and Frost Resist being 1 of the exceptions to the limit, you could use Comfortable Clothing for those stats (irony there though, is the frost attacks are the weaker 1s they have up there). Also, I'll bet in your current armor Sundered only puts you a few points below maximum, which is good since a bug in the elf crypt quest will turn off imunity to that debuff in an entire item slot with the item that has it for the rest of the game.
Oh, and you said yourself those stats do other things, so decide if it's really not worth salvaging in total.
To everyone else: What defensive stats besides Armor, Warding, Focus and Frost Resist can you even raise past 75? Doubt there are any in my current build, but what's possible in general?