Well, those parts of RDP are nearly dead now. These days windows does basically all rendering on the host side (including 3D), and sends bitmaps to the client. Even fonts are rendered on the host side, ever since ClearType has been used.
The main exception to that strategy is that desktop compositing does get done on the client via dedicated compositor commands.
The experience of RDP *is* vastly better than VNC, but that's not because it's using primitive drawing commands -- that strategy stopped working out very well years ago.