I agree with kirillsasin even if I don't hate MLP (I don't particularly care about the show either) myself. Officially adding a race that departs so much from pre-established internal lore of Strive make them feel very out of place. And honestly, if Halfkin/Beastkin Horse get introduced into the game there's really nothing to stop you from customize them into a MLP character.
Also, half-spider girls, slime girls and kraken girls aren't really unorthodox if you are aware of the Monster Girl community. It's just more Japanese than American.