Maybe there's a reason this hasn't been done, but a cursory search hasn't yielded any discussion on this:
Since the majority of detail for a model is in the outer shell, could we gain the ability to have the outer layer subdivided to the overall layer height? I don't see how this would cause print issues (except possibly laterally) because you could do 1/2, 1/3, or 1/4 passes then proceed with normal height through the infill, bottom, top, and support.