I know that it's been theorized before that Azeroth's ultimate threat may turn out to not be the Burning Legion, but the Pantheon of Titans themselves. I hadn't really taken this seriously until recently and I was wondering what people thought about the idea that every time we save Azeroth, we're in the end giving more and more reasons for the Titans to ultimately fear the beings of Azeroth. This would ultimately build up to the point where we kill/defeat Sargeras. Thinking about that from the Titans' point of view, sure it's good that Sargeras has fallen since he was sowing all kinds of messiness, but what of the beings that brought him down? Before he went dark side Sargeras was the freaking muscle of the Titans.
Given that the Titans' watchers have pretty much already decided that the planet has been thoroughly hit by systemic corruption (though word of this hasn't quite reached the Titans yet), and the knowledge that a bunch of creatures- many of which were titan creations corrupted by the Curse of Flesh -managed to bring down your ultimate warrior? Seems like a pretty good reason to be worried about a little backwater planet called Azeroth.