Posable breasts
I would like to suggest that breasts become posable or at least rotatable.
I know you guys worked very hard on your boober physics and everyone here and perhaps the dead or alive beach volleyball guy is very thankful for your work. But right now there's no way to make a character look like they're believably holding up a boober with their hand, or getting pushed up by a leg or wherever you'd find a boober in sexual escapades.
Being able to pose breasts would allow for stronger character posing, and would pay off in spades when interactions become a thing. Imagine all the paizuri, man!
I think an optimal way to pull it off would be to make them rotatable similar to how certain family jewels were rotatable in YL1.
I guess it could be useful in cases where allowing artistic control to override physical consistency might be better, but those seem like edge cases and movement consistency across interactions seems like a more important aspect imo.
I guess for single images it's still a strong case, since it's not like the physics are present in the output anyway.
I think physical interaction to some degree is the end goal. In the meantime, being able to "pose" Physics bones for screenshots could be a cool feature even in the long term, but ultimately low priority.