Take the following with a grain of salt. I've heard some stories and theories about the figure.
1. No way PHICEN/TBL would have made a deal with TOYS-ERA to use their seamless body.
2. TOYS-ERA supposedly approached JIAOU DOLL (or the other way around), but a deal couldn't be made due to $, design, and quality requirements.
3. The primary issue TOYS-ERA faced was achieving the design requirement for the figure's skin texture based on the original prototype.
I wonder if they could have just created a skin tight blue outfit instead to fit over a regular body? Since that's essentially what Lawrence herself was wearing by the end of the movie series, to avoid having to be completely painted up every day.
Or like others have said, even a jointed body would have been better than nothing.