Just a crazy thought: Having a Blender style plug-in manager might encourage more developers to add tooling. However, the entire UI would need to be extendable to support plug-ins effectively.

Sunday's Digital Art Live / Poser 12 free webinar had mention of something similar. The team's hope was said to be to bring as many as possible of the useful old PoserPython tools into one unified menu/panel. And at the same time upgrade these useful scripts for the latest Python version, and thus for Poser 12. It won't happen overnight, though conversion work is ongoing now and having success, but that was the stated aim. Since so many of what people call "plugins" are scripts or script-based renderers (also stated was that Octane for Poser will be making a return to Poser 12, very shortly, as a plugin geared for the latest subscription Octane) then that more or less covers what you seem to want. There will also be simpler "one-click" ways of installing purchased content and scripts, and this will apparently be "multi-store" not just Renderosity. They are also working behind the scenes on re-tooling parts of the UI with Python 3, which (though not seen by users) opens up long-term possibilities re: re-working the various panels. There are other moves toward Poser being more "Blender-like".