I tried playing as a Midlander once as well, as I'm also not to fond of having cat ears and a tail. Alas the height was a bit to much for me. While the difference between a Miqo'te's shortest height and a Midlander's is only a few inches I really could feel it. I felt way to tall, awkward, and slightly distorted the one day I played as one. Which is why in my original post I made of point of being the same size as my minimum height Miqo'te, as it's the only height I think I can feel comfortable as. Though, if I had no choice but to be a few inches taller than I am now, I'd learn to live with it, I guess.
As far as animations go, I have thought of an interesting idea that might save SE a lot of work with this. It makes little sense for Half-Elezen's to have their own way of bowing and waving when they're just a mix of two current races, they'd just copy whatever they grew up around. So instead of two "Clans" they would have two "Upbringings" (or whatever SE wants to call it). "Elezen upbringing", and "Hyur Upbringing", Character Customization would be the same for both, but your emotes and animations would be borrowed from the main race of the upbringing you picked. I myself like Elezen emotes, so that's the one I would pick.
Some people wouldn't like it cause of the whole re-using assets = lazy thing, but seeing as we're not likely to get this in the first place I'd like to present as many cost cutting options to SE I can in hopes they might really look into it at some point in the future.