A couple of thoughts that I haven't seen touched on too much yet:

Python:

I'd personally would love to see a couple of changes in Poser's Python implementation.  First, the ability for Poser ot use a non-embedded python interpreter would be nice, that would address a lot of issues of scripts designed to run on one version of poser not being able to run on another.   Also, the ability to make python scripts more accessible to folks who are a bit less technical I think would be a boon as well.  I use a lot of python scripts myself and just getting my favorites setup on the default menus is a bit of a chore, and then of course having to run the menu first before selecting an option is a bit of a pain after the first 30 or so times.  Having an easily accesible python menu that works more like the library section does would be fantastic.

Memory Bug:

This one has been an ongoing issue for quite some time, as you increase the size of Poser's default library the application itself begins to slow down and eat more memory, and even if you switch to extenernal runtimes that memory never free's itself up.  This is a horrible bug that really needs to be addressed before your next release.  If you do nothing else for your next revision, fix this.  It has been a problem in Poser for a very, very long time and it makes the application seem, well, at the risk of sounding harsh, like a 2 bit hobbiest app.  There is no reason why Poser should eat up a ton of RAM just because you have a large default library, much less never release that memory back to the system. 

Face Room

If your going to keep the face room, make it so you can load and use external geometries for various figures like V3, V4, M3, etc.  Otherwise get rid of it or make it an external module of some sort that doesn't load by default.  The face room is useless for most of us because it only works for Poser's default figures.  It's a grand idea, don't get me wrong, but honestly it's too limited in it's current form to offer any real value. 

Content Tab

Ditch it.  It's annoying in the extreme and a total waste of space.  I don't shop from within an application and neither does anyone else, if you really want something like this setup a menu option somewhere that loads the default browser and points it at your website.  Taking up an entire tab for this was a terrible idea from the get go.

Firefly Renderer

Again, this is one of the biggest bottleneck areas of Poser, the rendering system.  A lot of us use Poser for posing figures, but most of the serious artists I know don't use Poser for rendering because firefly is, well, again just being honest, way behind the curve in terms of rendering capabilities.  My suggestion would be twofold.  First, in the next release of poser give it the ability to very easily select and use a variety of external rendering systems of the gnu variety.  Renderering systems such as yafray and the like.  Then take some time and overhaul the firefly rendering system to make it much more competitive with what's currently available on the market.  Firefly needs a ton of work done, more than I think you could reasonably accomplish prior to a next revision of Poser.