I think this will be less taxing to the CPU if the majority of the graphics runs off the actual GPU. Example. A lot of the plug-ins have meters, or some graphics that moves around. The bigger the session get the more taxing it is on the CPU. This will also be helpful if you have a quicktime or wmv movie in the session. GPUs are now powerful enough to work as a second or third processor. Running video and graphics off the video card would make perfect sense.
This feature would be great to, and will go hand and hand with 64-bit because you can access more resources within the GPU (Like more than 1 or 2GB of RAM). This will also help leverage the work the CPU have to do, giving the operator more processes towards plug-ins and VIs, as well as smoother video playback on a singe system. You can also run a High resolution waveform as in this post http://protools.ideascale.com/a/dtd/Detailed-High-Res-Waveforms/12659-3779 Details.