I wasn't very happy with the ending cinematic of Cataclysm. The whole thing felt like a re-run, as if I'd seen this movie before. And Ag'ra's pregnancy was just the cheesy center of a cheesecake sandwich. But then, I stopped thinking about cheese and started to try to think of it from an old-god perspective.
What if this was what the old gods wanted?
They put their cards on the table, field their entire army, however feeble it might be, release their strongest lieutenants into the wild and say, "Go. Wreck Azeroth." All the while, they knew full well the army they unleashed, their champions, even Deathwing himself, could not possibly succeed. But success was never their intention.
When the Titans left, their caretakers were the Aspects. It was among their list of charges to keep the old gods in check. How well they did this is debatable, but consider what Deathwing does from an old-god perspective. He creates the Dragon Soul - an object so powerful that it's capable of defeating the Burning Legion - but also an object infused with the essence of every Dragonflight. This diminishes the Aspects, but not enough to matter.
For the old gods to escape, what they really need is to be left alone by the Aspects so they can pursue their agendas.
In comes the Destroyer - who must himself be destroyed if Azeroth is to continue. The Aspects can't do it alone. They need the help of the mortal races - but that's just a distraction. The old gods are still playing this game - and what they really need is for the Aspects to channel their essence into the Dragon Soul to destroy Deathwing, thus diminishing themselves permanently.
Which is exactly what they do.
At the Maelstrom, emerges in full out old-god mode and we were just the catalyst the old gods were waiting for, and at a time when they sensed everything was in place, they played their cards. Nihilistic fool that he is, Deathwing never suspects his true purpose and dies, taking with him the last of what made the Aspects great.
The old gods's hand might look like a mess, but the last couple of cards have yet to be turned and that hand might turn out to be a flush. If you were an old god, you'd be pretty damned happy right now, wouldn't you?
The keepers are gone. There are no more aspects, and the mortal races don't really know or understand the old gods enough to face them down. Without the help of the Aspects, we're on our own against all of the old gods.
We've already seen C'thun come back in the Cho'gal fight. Who knows how quickly Yogg'Saron will return. N'zoth is still out there, and we haven't seen any sign of it at all. Our best hope may lie in the fact that the old gods hate each other almost as much as they hate us, and in that conflict, we might have some hope of victory.
But man, this is a good time to be an old god.