.@Selcaer Definitely subject to change, we're now fine tuning each face, altering base pose to more closely match original structure/emotion- Chris G. Robinson (@artofcgrobinson) July 5, 2014
The base animation is the default expression on a model's face when they are not in any kind of active motion. It's the expression your character has when they are simply standing around in town, or on the character creation screen. Currently, the human female models in the beta are all wearing the same expression while they're standing around. With updates to the base animation, and the tweaks to eyebrows and other facial features as tweeted by Robinson, the models should once again appear just as diverse as they do on live servers.