Honestly I think if I ever got one I would just use it for cuddling and cuddling it to sleep like a bodypillow.
I assume you are some kind of manufacturer doing market research so:
Sleep quality (I assume tiddy hugging , sleeping on and around her ass, on and between thighs or hugging her ribcage will be common so consider how those feel)
Body heat that can run for extended time periods without being a fire hazard. (Maybe there is a way to do this for cheap by using the guy's bodyheat but being good at mimicking the fact she has internal bodyheat after that?)
No idea how realistic the bones, fat and muscle is on a sexdoll... or maybe there is something better than realistic (hyperstimulus) but I assume realistic is a good starting point.
Ribcage having appropriate springyness and boney parts will likely contribute the most to "bones" here
Weight could also be something to be considered. (as said)
Perhaps shouldn't be too realistic as you could end up in a uncanny valley where you go from realistic cuddlepillow to "fresh cadaver-like".
Also for the anons that basically fantasise about robot girlfriend I think that will be horribly expensive (repairs excluded) in the forseeable future within our lifespan and would not end up as actual customers.
I think even by glorified bodypillow with very rudimentary ability to "hold you during sex" with a button press would be expensive. (Esp the bodyheat and R&D for this kind of stuff)
Like even a basic hug or leglock would set you back a king's ransom.
It's obviously a partial replacement for those unable to have the real deal.