Yes, and it works way better with screen sharing for some content, which is most, nowadays.

Take for instance a big 3D game. It is much more bandwidth-efficient to compress the frames and send that over than to send the 3D models, textures and transformation matrices over the net. We still don't have PCIE Gen. 4 bandwidth for networking.

Okay, this is an extreme example. But most apps (just take Firefox as an example) send bitmaps over X forwarding anyways. I use Xpra for these, but waypipe should work a lot better, in theory (less round-trips, etc). Of course, it's better if the graphics toolkit is install at both ends and can render the stuff locally (which was the intent with X). AFAIK a few support that, I wonder if rdp doesn't specify something to negotiate its use on a per-client basis?