Yes, you can work at the higher level and return to the lower level while retaining detail - at least in ZBrush and, I would imagine, the others I mentioned

The higher level is, in most cases, used to produce a normal or dispalcement map which can be applied to the lower level model. For a model in C4D that would be applied to the original base model dropped into a HyperNURBS with the required subdivision level. That's about the limit of what I've picked up.

I think you'd still need to pay attention to the basic edgeloops to avoid any unexpected deformations when animating/ deforming and it would be wise to model the major forms rather than trying to do too much with the sculpting.

It's very appealing but RGB normal maps only seem to be supported in the higher end apps at the moment.  They allow the surface of the model to be displaced in 3 dimensions rather than just a +/-% option of a greyscale displacement map.  They'd allow things like caves and overhangs in a terrain formed from a plane. In that respect they allow you to push the modelling to greater limits but how advisable that is I don't know. I'm going to have to wait until the technology filters down to the lower end before I'll be able to find out. :)