"The power of the higher-end software is in use of procedural objects and deformations (NURBS, HyperNURBS, SPDs, and so on)." Blame the content creators - FireFly supports micropolygon displacement and Bezier patches (Polygon smoothing). You'd have to cut compatibility with P4, but then you can get fully detailed figures without high poly counts. Displacments can be animated and joint-controlled, so you don't loose flexibility.