[Update #2]: The Rise of Azshara patch has now finally arrived!
[Update]: Blizzard has now released a short comic detailing what Mechagon and the Mechagnomes are all about!
World of Warcraft's long awaited Rise of Azshara update has been pinned for June 25th, just in time to offer some friendly competition to Final Fantasy XIV's Shadowbringers expansion. In terms of content, the biggest thing coming in with the Rise of Azshara update are definitely the two new zones riddled with quests and mounts: Nazjatar and Mechagon.
You can also expect to see a rather significant overhaul of the Heart of Azeroth system in order to make it a bit more engaging to mess around with, Heritage Armor for Tauren and Gnomes, a whole bunch of new profession items to create, and naturally, an assortment of balance changes. There will also be a brand new raid set in Azshara’s Eternal Palace, though that one will only open on July 9th.
So if you're interested in all of the details, as well as what sort of balance changes you'll potentially need to deal with, you'll be glad to hear that Blizzard has now released the full 8.2 patch notes. As expected, the list is absolutely massive, so do be prepared for quite a ride.
On the other hand, if you don't have 30 minutes of free time or if you're just looking for the short version, I'll leave you with the recently posted patch overview. This one is obviously a lot less in-depth, but it should still get you up to speed on just about everything Rise of Azshara has to offer. Enjoy!