Sure, four is overkill, but perhaps not two?
- Besastkin pony
horse tail, ears, fur, and horse-like stats (+endur, - intel).
Possible hooves and digitigrade (backwards bent, walking on toes) legs.
- halfkin pony
horse tail, horse ears,
human hands, pantigade feet, and human skin
And an option in lab to add wings or horn(s) to any girls we want.
Actually I wonder if races could be handled like sexes (now, if you give a woman a penis, she becomes a futa, and if you later remove her pussy, she becomes a man).
I mean, instead of having halfkin and beastkin ponies, you'd just have "ponies": the game would check their animal features and say if they are half- or beastkin ponies, depending on how much furry they are (for instance: torso: 20%, face:15%, legs, arms:10%, hands, feet/hooves: 5%, tail:5% and so on. If the sum is over 25%: halfkin; over 50%: beastkin).
Through lab mods, a character could turn from halfkin into beastkin (or into human), or even change its race. Also, their children would inherit features their parents already have, even if un-natural (e.g. a horse with feather wings could have winged children, despite wings not being equine features).
It isn't easy: the more I think about it, the more questions I have.
For instance, as d.stu said, some races differ very little.
Another thing: while the halfkin<->beastkin change can happen automatically, I'm not sure about the race reassignment. Imagine if you have a seraph, you cast a Mutation spell on her and she loses her wings: should she become a human and lose her racial traits (and boosts)? Well, some players would find it cool, others would not.
Things would be different, though, if some boosts depended on your body, instead of your race. E.g. wings should give you more agility, no matter what you are.
I would be very OK with all of this.
Maybe change it to exactly 1/8 sizes, for consistency.
System isn't perfect because for some races the only physical difference is pointy ears (elves) or wings (seraph) or whatever.
