That's exactly my thoughts. Actually, 3dc is great 'only' for building a shape in voxels, retopo, paint or detail a model in Pixel or micropolys. And that's already a LOT of things.
Zbrush 3.5 will allow you to extract Displacement and color maps from HD geometry. HD geo is a smart way to create subdiv models up to 1 billions polys by caching on disk details stored in HD mode, and to display/sculpt in HD only the area you want do detail. (You can also render in Zb the entire HD model)
On my previous Pc i bought in 2005 (Xp 32, 2 Gigs of ram) i sculpted and rendered in Zbrush a scene composed of 2 models : 1 of 20 Millions of polys, the other one of 40 Millions of polys. I was still able to edit, sculpt and pose a low rez version of each model.