Just in my opinion, what Poser Pro NEEDS.

1- Full 64 bit support, in all aspects of the program.

2- The ability for an idle CPU core to pick up on parts of the render not yet completed. As it is, when a core finishes its task at hand it sits there idle, doing nothing.

3- Global controls, such as the ability to turn on or off all shadows for all lights at once. That would be great for when you're worrying more about how your textures look than getting a real render. Certainly it would be much better than having to select each light and turn its shadows on or off one at a time.

4- When creating a new light you should be prompted to name it right then and there, and the shadow cam for it should relect that name, not something stupid and nondescriptive like "Shadow Cam Lite 432". They should also spell "Light" correctly. ;-)
Speaking of lights, they should also come in at 0,0,0 with no funky rotation, maybe just pointing straight down the Z axis.

5- The ability to abort a render as it's calculating shadows and/or loading textures. You may realize something is wrong or you forgot to do something the second after you hit CTRL+R, but have to wait until all shadows and textures are calculated before you can abort. That can take a long time in some cases.

6- Why is a camera which is "pointing at" a figure MUCH slower in OpenGL than one which is not, especially if that figure has IK on? That's just... weird. Annoying, too. Why is a face camera, for example slower than the main camera? Because it's "pointing at" the face. You can move the main camera or the auxiliary camera to the face and it is much faster.
The hand cameras are the same deal, much slower because they are "pointing at".

These are just a few things I've been thinking of and that have been bugging me for a good while now, and I'm sure there are more I haven't thought of as I'm writing this. Basically, ideas to speed up the process. Things "Pro" apps tend to offer you control over.