I can see his issues.
cons:
I think those animations where the bow is just being flailed around like a sword looks bad, perhaps deleting those key frames on that arm, so that instead of flailing around, the bow arm is steady. the other hand could be doing large arm swings, to signal people behind to come forwards perhaps? either way that animation needs work. the bow clips with the horses body and head horns.
the bow attack animation you built has no arrow showing going from the quiver to the draw (is this just the viewer?) either way an arrow should be pulled out and quickly vanish. it also seems a tad bit slow. perhaps deleting small chunks of empty frame between the bones animations to make her shoot faster, never fun to try to rig that in the world editor.
pros:
the undead race has always been among my favorites from since forever and I always loved the idea of non skeletal zombie archers, I always wondered why Ms.windrunner was always alone as the undead archer lady, I mean enough night elves died to explain it as a standard barracks unit to ME ANY WAY. crypt fiends though what the hell. (there still cool though)
I like the mesh, her legs don't clip too much and the amount they do is not un fixable. I like how shes scaled to the horse. I like how she has nice head movement and what not. I know your cannibalizing bones and that's good and proper, yet Im still amazed at how good it looks. I like this concept and race and its immensely useful when paired with the blank horse and the mpq dark ranger file. mounting/unmounting models are always good for usefulness.
Suggestions:
I think you could add more details to her horse, such as perhaps a second quiver of arrows on top of one of the horses shields, it could still move with the shield and be attached to the same bone and simply be a secondary ''spare'' quiver. not much other then a copy/paste really. perhaps if not another quiver could instead be a bag or any other array of items.
her cape could be more wiggly maybe. other then that seems like a nice model its very close to complete in my view and because its such an iconic hero its very useful 8/10 as of now. 9/10 if you could add more spells with her free hand, different hand motions. perhaps spells using the horses head.