Now, this is spoiler-heavy, so if you don't want spoilers for patch 5.4 content, of any kind because while the video doesn't contain that much it could spoil something I never even thought of, please don't click the video. Also, don't click the break and read more of the post, and don't read the comments! Spoilers lurk within.
So we start off flying from the shrines out towards the Serpent's Spine, then spin around and head back in. Even the least eagle-eyed viewer will notice that there's been a considerable sha infestation in Pandaria's bread basket, and that the daily quest hubs have been completely wiped out. It seems from what players on the PTR have been saying that these dailies are now a feat of strength, but of course this is PTR, so take it with a pinch of salt.
Heading back into the Shrine area, it's easy to see that the statues are in a pretty bad way, and that all the water is gone from the central zone. In its place, there's just the tell-tale black ground left by the Sha, and what could be some kind of old god thing emerging from Mogu'shan Palace. Could this be related to what we discovered in the Dark Heart of Pandaria scenario? It seems likely.
And lastly, we see, as the water is gone, that there is a new, hidden entrance to a raid. This is supported by the Dungeon Journal, which currently only has one boss within it: Immerseus.
The corruption unleased within the Vale has animated and twisted the waters of the pools, causing them to coalesce into a massive water elemental
What do you think of all this? It seems likely that this is caused by Garrosh and his cronies, but I'm surprised the raid begins back in Pandaria, when it seemed that the Battlefield: Barrens content was leading us to begin in Orgrimmar. Whatever happens, it was really quite a shock to log in and see the devastation.