One thing you certainly won’t be able to do in
Shadowlands is raid with the opposite faction.
There’s no plan to end the Horde vs Alliance divide.
However, another old question was answered with a resounding yes.
We will be able to transmog Legendaries sometime soon. The dev team is also,
adding additional customization options for humans, including darker skin tones, curlier hair textures, and different eye shapes. Trolls and Dwarves both get warpaint options, and Undead will finally be able to hide their bones.
If you just can’t wait to get to the titular Shadowlands, you may want to pre-order now, because if you do so you get access to Pandaren and all the Allied Races as Death Knights once patch 8.3 launches. They’ve added an additional Collector’s Edition, so make sure you
figure out which one you want before you buy.