So, was doing a little research on npr/anime-like modelling/texturing and took a look at the Ace Attorney models available here, specifically Phoenix Wright.
Inspecting the model, I noticed that they've a bunch of alternate parts for upper and lower faces and hands.
Trying to guess why the model is setup this way, my friend and I ended up with two theories:
1) This is how Ace Attorney 2D games were built (parts swapped in on sprites based on the script markup), therefore it was a natural technical progression to do the same in 3D. Seems a little odd to me, as these games were built on MT Framework Mobile, but it's possible the deformation features hadn't been implemented at that point?
2) Limitations on 3DS (tri/polygon count, lack of blendshapes or limitations on model bones) made it more efficient to swap in different models rather than have a model with the tri/polygon density needed to support all the deformations required - easier to have bespoke models with smaller polycounts.
It doesn't seem like this technique is replicated on the later The Great Ace Attorney Chronicles, which seems to feature either facial bones or shape keys or a mixture of both (and, man, what great work...!).
Any ideas, folks? I really know nothing about 3DS hardware or MT Framework, just kinda curious about why the model was setup in this fashion.