Good question. I think that we are more or less feature complete for a 10.0 version but I don't know how many stuff is on Toxie's to-do list which he wants to add to the 10.0.
The only thing i wanted to get really finished was that the environment map could be replaced by a custom one (and support HDR formats like .hdr or .exr), but given the time i can currently put into VP, i wouldn't bet that i can get that finished in the VP10 timeframe. But its also something that will not break backwards compatibility or something, so it can be added to VP10.1 easily.
The other stuff is all mainly minor things that also shouldn't break compatibility (like being able to rotate BG elements, etc).
Then of course the big topic of the "automatic" FS/cab camera setup and the currently weird stereo3D parameters, but i guess this can also wait til VP10.1?