Heads up for Warlocks: we're finally getting new models for all of our demons, even the ones who aren't upgraded by the Grimoire of Supremacy. Here's a video which gives a peek at the Doomguard, as well as data-mined images for some of the others.
Also, those who are looking for something to use their Garrison resources on, the upcoming Shipyard will require a lot of resources. The Shipyard itself will require a short mission chain and, on the PTR, currently require 5000 garrison resources. The first basic transport ship currently requires 1000 garrison resources.
So, unless things change from the PTR to live, you're looking at about 6000 garrison resources needed to unlock the potential of the new shipyard missions. Ships themselves will apparently also have rarity levels, like followers do, and might be equippable with trinkets that will cost yet more garrison resources (one person reported one being about 2000 garrison resources)
Stumbled across this channel a day ago and it provides an interesting look at World of Warcraft zones, instances and raids in ways that aren't possible in live. There are also videos showcasing zones that were drastically changed from Vanilla (when they weren't available, yet already in the game), like Caverns of Time and Black Morass, Hellfire Pennisula and Mount Hyjal; and areas and secrets that never made it to live.