ZeroSumGamer said:

Their anuses are too close to their pussies.

In case you didn't know: Vulva's are rather close to the anus. Especially on equines. However, the main problem here is that they are using incorrect anatomy AND incorrect placement... and proportion. They got human asses on this, which doesn't work at all. The vulva's are placed on their stomach, which DEFINITELY doesn't work as it goes through the pelvis, and the anuses are kinda tiny and just slapped on somewhere in the "human butt-crack".

So... basically they'd really need to revamp their entire genital drawing design. Equine anatomy would do them a ton of good, as then they can impossibly mess up the placement part at least. (unless they fail really hard) They got a quite good ground otherwise for joins and poses.