A lot of parallel plots were going on in Cata — Azshara was prodded into action against Neptulon at the same time Deathwing was let loose, and this was shortly after the Emerald Nightmare plan was somewhat derailed by Malfurion's interference.
It's a nice idea that N'Zoth just plays with a million pawns at once and whenever one goes down, he just shrugs and starts building up the next one in line. Kind of a meta-aware Old God that says, "Yeah, every expansion they defeat the other guys' big plan so let me just assume they'll do that again. I'll give the heroes some nice loot-filled decoys to deal with and sooner or later they'll mess up enough I can capitalize on it".
Would be cool.