I feel like i should raise another issue - the fact that undead greater vaults exist. Undead creatures are a pain in the butt, and emperor liches are overpowered. Not only do they drain stats like it's going out of style, but they're nearly unkillable to boot, and that really is a problem, as a greater vault may just become unclearable thanks to that. And that is without even mentioning the rest of it, which can be very problematic indeed.