While playing I have been writing down tweaks and other ideas I had.

Be able to pass time without leaving your apartment.
Fix pool ladder...lol
Once you have the motion capture down with physics, it would be nice to be able to other non-sexual activities. (Take a shower, sit on the couch, etc...)
Incorporate an Auto-Stroke button for the intercourse.
3D hand for interactions. (Picking up objects, Breast squeezing, grab her head to turn, etc...)
In the Fast Sex mode: Be able to bring any girl to any location with any pose.
Custom user clothing textures.
Increase your characters grab strength. Maybe this is done by exercising. (Level building?)
Be able to tear a girls clothing. Maybe once strength has been leveled appropriately.
Have a Quick Save or Room Save function that will save the current location of all of the furniture in the room. I hate when I drag items for custom poses and then it gets reset when the game is reloaded.
Previously mentioned, Player Character training: Strength, Endurance, etc...
Make the PCs dick stiffer either through pills or training.

Well thats about it for now. Will definitely be playing more.

Thanks for reading.