It works a lot faster then 2.79. Aside from aesthetics It seems to be just proper coding vs shoddy work that was pieced together.
it obviously still has its downfalls and issues.
For instance (at least until you can get the latest version of my addon) you cannot export animation curves along with your FBX.
And, well the whole import export FBX addon is still pretty bad in terms of implementations of the Autodesk file format but it does do what you need even in its stock version without curves and all that jazz.
I have been coding plugins for it specific to UE4 for about a month or so this far.
The difference under the hood on the way things are handled is immense in reality.
starting with class and module registration and ending with preventing silly mistakes on the coder’s part by just not allowing some bad practices.
Anyway.
in terms of handing the animation with facial expressions and all of that, you should just take the time to extrude the 2.
You can completely recombine the face by attaching it on top of the base skeletal mesh like they do for many games including Forthnight.
basically there is no need to have movement and facial expressions tied together ever since .18 according to the fortnight animator talks.
this is basically why I came up with my current plugin, BoneBreaker.
I needed an easy way to author / create / correct marketplace animations so that I could then re-target my skeletal mesh onto them and animate the rest while being 100% sure the underlaying movent is exactly what I want.
Right Now I’m basically playing chicken with Blender waiting on an official release date in order to release the Animation Curves addon as part of Bone Breaker and as a separate export entity.