One very simple feature, easy to implement:

It's trivial to map between Poser's vert order and the original OBJ vert order. 

When exporting OBJ, a checkbox for "export original OBJ with current shape" would be easy using that map.

I do this right now as a blender add-on.  It takes a split second.  There are 3 meshes needed: original, zero'd poser ordered (used to map the vert map), morphed poser ordered (vert positions in poser order).  The add-on takes those and produces a copy of the original but with vert positions from the 3rd (using the vert map).

I use the trick of being able to dict key using the vert x,y,z.  I even allow a precision, but thankfully Poser doesn't mess with that during figure creation.  The poser ordered verts have the same xyz as the original, just a different index.

Since poser has access to all of that, it's just a matter of calculating the map and using it during export.

I was going to keep the map inside the Object (as a property) since it only needs to be calculated once.  But it's actually nearly as fast to calculate as it is to read the property. And being "calculated on use" keeps it real :)

By being able to export a morphed original OBJ (usually unimesh), a lot of what people want unimesh for would be achieved.  Without any changes to the underlying figure system and with an amount of code that could be written by a single person in a single day. :)