My Robot Nation - You design, they 3D-print

By ruin it, I mean to say, up until that step, everything is just "select from this set of body parts". If you kept it as a "select from this set of body parts", they could use any material they wanted and just injection mold all sizes / all body parts, and assemble them to order, just like dolls. That allows moving arms, legs, and head as well as allows rubbery material selection and color options.

The option of using standard molded parts only goes away on the last step, when you add the random features which then force them to use 3d printing. In my opinion, those features are not worth the loss of manufacturing flexibility that they cost.