There have been a lot of model updates datamined recently, and now you can look at all of the new Legion models in Wowhead's updated Model Viewer for Legion, right here.
As a game that has existed for over a decade, World of Warcraft has seen a number of graphical improvements to the original models of various monsters, NPCs and, as of Warlords of Draenor, even to character models that constitute the various races players can choose to play as.
Reddit poster Exil_ noted an unnannounced patch 6.2 change yesterday -- it appears that the female Human model has been updated. A quick look on the PTR reveals that female Human models have been retouched, and some of the textures for female Night Elves were also adjusted.
At first it looked like all I had to write about for the patch 6.2 warlock changes was that Demonology was nerfed pretty hard, but then I found some things like next tier's set bonuses and new demon models. So let's get to it. Mind you, the caveat about the PTR changing is always there, moreso now when we're at the beginning of the PTR.
Not everything that's coming with Patch 6.2 is available for player testing just yet, but the dataminers have already yanked plenty of models and maps out of the patch on the test server.