Quote - In the past, whenever I've had issues with a given Poser scene -- I'd estimate that approx. 90% of the time the problem cropped up at the end of the scene-creation process: during the final rendering stage.

That's usually the case, even in highend apps.  Even in some studios I've worked at, sending frames off to render was always the part of the process where we held our breath, and always the part that presented the most opportunity for something to go wrong.  Technical Directors were always pacing the floor, ready to come up with a solution to a render issue.  That's why rendering in passes and having more tweaking options is something all professionals and serious hobbyists should want and need.  We always did a lot of the major color adjustments, render effects,  and lots of compositing in post, and rendered according to that theory to get the most consistant results.

Quote - Once again: Poser Pro might serve to fix that.

Yes, it could.