Savur from Gurubashi asks, like an Azerothian Jerry Seinfeld: what's the deal with Mount Hyjal? Escape from Durnholde and the Black Morass, the first two Caverns of Time instances, have to do with players attempting to stop the Infinite Dragonflight from completely messing up the Warcraft continuity. In both of those instances, you work both for the events of history, and against the Infinite Dragonflight, in order to make sure that what really happened in Azeroth actually happens.
But in Mount Hyjal, the Infinite Dragonflight is nowhere to be seen. There's no reason for the players to be there, as even without them, Archimonde was defeated by all the exploding wisps. Now, the Bronze dragonflight does apparently claim that they suspect the Infinites are there, but from all player reports (disclaimer: I haven't played the instance myself), the Inifinite Dragonflight is MIA, so there's no reason for the players to stick around and fight.
Drysc wimps out, and basically says that players are there because it's cool to see past events of Warcraft history (and that Archimonde apparently drops the Professor Plums). But that's weak-- if the Bronze Dragonflight really cared about protecting the continuum, they wouldn't just let a few punk heroes go sightseeing throughout time. Sure, there doesn't need to be a "lorelol" reason to fight the people (and Orcs, and Scourge, and the demons) that we fight, but there should be.
So we'll wait patiently and see what happens in the next CoT instance. Are you content with just seeing the sights of Old Azeroth, or would you prefer there be a reason that you're going there in the first place?