"I've just realized that I'm rapidly outgrowing the program itself, and that Poser's development is not at all keeping pace with available technology in many key areas."

That seems to be the common point. I have always considered the last couple of versions, nothing more than point upgrades. That is why I have invested most of my time and money with higher end software. I still use poser for rigging and the walk designer and quick storyboards but it is getting less use as the tech of everything else is advancing.