Bringing back to life Warpstone Excavation (only for Skavens) is not a bad move. It gives me as a player opportunity to include it instead of Innovation or some other restricted card. With the limited keyword it shouldn't be to overpowered (Contested Villages won't come at the same turn), instead it allows you to use its corrupting properties to made some nice decks with fluff. As we haven't yet played any big tournaments with this new faq it is quite hard to state that it's gonna be overpowered. If that happens, i do believe some changes will be made in next FAQ. After pulling the plug for WHI by FFG, however in "Undead" state, it's still a Living Card Game and when sth will go wrong we can expect FAQ changes a bit sooner than usual.