You have to hand it to Blizzard, they are taking Legion's content flow very seriously. World of Warcraft's Patch 7.1.5 has only recently arrived to the live servers, and already we have Patch 7.2 making its way to the PTR (Public Test Realm).
Most of Patch 7.2's major features aren't enabled just yet as the primary testing focus for this build is the newly added Demon Invasions and general stability, but there is a lot of awesome stuff hidden behind the scenes. If you don't mind spoilers, and there is a whole bunch of them, you can find all of the recently datamined information over at MMO Champion. There's bits and pieces of the upcoming Tier 20 armor set, new Class Hall research, class mounts, new character models, and so forth.
If you would like to give the PTR a try and see what Blizzard has in store for the future, simply change your region to the PTR, after which you will begin the download. And as a final note, here's a couple of images showcasing some of my favorite new mounts: