Oh wow! What a way to end the main story and set up for the expansion!
Can't really say much else, because pretty much everything is a massive spoiler.
FFXIV is simply the best MMO on the market at the moment. I am eagerly anticipating Heavensward.
Edit: Also, I can't believe I forgot about this because of all the stuff that happened afterward, but the new 8-man fight is glorious. One of the best dragon fights I've seen in any MMO. It's not very complex, but tells its story perfectly, and has a great enrage mechanic.
(Warning: there may be spoilers in the comments.)