Bit of a loaded questions don't you think.  I am quite sure the render engine is multithreading capable.  Much of your performance issues could be your computer, what is its specs.  The content system is what it is and you need to put in time and effort to learn it, once you do unzipping zip files will make sense too.  Don't blame Poser for the fact Wings3D is a box modeller.

Edit: dang my slow typing.