I say, it’s pretty hard to make such a nightmare look good. As I had to “take a guess”, I’m thinking his style is going for realistic horse so I corrected it along those lines.
 
Atleast Derpy might be able to stand now like a normal horse. There’s a reason why anthro horses have their ankles so low. If you were going for anthro with those legs, then Derpy couldn’t stand up bipedally like that. If you look at a horse’s anatomy or even Baron’s anatomy then you see a huge difference in his anthro legs and horse’s legs.