Great job so far! A few things that I would think would be great.
Ways to dominate the models, hair pulling, choking, tit slapping ect.
Realistic Cum that can be controlled and shot anytime on any part. Actual fluid dynamics. Very high limit of how much can be used. Probably a bitch to program I'm sure.
Realistic B hole.
Correct looking everything when the model is bent over in doggy position. Connections and shape of ass and legs.
Keep up the good work