Three things come to my mind when I think animation changes.

I've always disliked how female characters have side-saddle riding animations for the horses, I'd at least do a /cpose to swap between side-saddle and normal riding.

I can't play female midlanders because of their running animation. I can't. Every time I actually load in as one and take my first few steps and see that girly girl run with the arms flailing all over the place drives me insane. I'd change that one without hesitation.

I'd change male Highlanders mount animation for the Flying Cumulus mount. After looking at it for awhile, I don't dislike it so I don't really mind, but the mount animation that makes it look kinda like you're surfing on the cloud is so much better.