I kind of thougth that everything I would do in any game would be meak in comparison. Because of that, I think I will mainly ignore the things revealed in CD, if I am not actually going to play an outsider based game. But for the most part, I don't think it will change that much. The only thing that will actually change is, that I will probably be thinking "Oh well, they are fighting against another warlock, but whatever, if the Outer Gates fall, none of this will even matter."
So yeah, it's probably best to keep the powerlevel down a bit. Your plain old apocalypse will do fine, destroying all reality might be a bit much.
DETONATE THE REALITY BOMB!!!
Damn, now that's stuck in my head.