Quote - Two examples of how good the Poser rigging actually IS:
XAA's improved Posette. Perfect basic rigging with a few "standard type" ERC controlled fix morphs.

Look at those awful shoulders, the flat ribbon elbows, the breasts that seem to be filled with sand and you can see how good Poser's rigging ISN'T. The morph brush is only a tool with limited use. It doesn't work with animation, cant add new geometry where there isn't enough to support the joints, cant change poser's horrible IK, can't add proper bone articulation in the shoulder or the knee, does nothing to fix the idiotic 2 bone spine, and dozens more such limitations and issues in the common poser rigging.

Rather then waste time on trying to fix these issues on the mesh, it's far easier to just do the corrections in Photoshop on the render directly. Or get yourself a real sculpting app like ZBrush or Mudbox and go nuts on creating models that are 1000x the detail/quality of what poser chokes on.

Quote - I was wondering what would make a real difference in upcoming versions of poser, something that would make it a must buy!

It's already a must buy for people who want a quick morphing/posing app. What else are you gonna use at this price ? Well maybe DAZ is becoming a serious contender. As for 'difference,' I dont see what they could add to poser that would make it attractive to anyone outside our little corner of the CG world. Most features they'v added over the past few versions have been mediocre at best, with a few notable exceptions like the material room. And even that is severely limited by not being able to use custom shaders. Maybe the rumored GI feature would be a good addition, but given how hard it is to make REYES do nice/fast GI, i'm not very hopeful.

Plus the thing is, as long as youre a casual 3D guy, you will be happy with Poser as it is. It's cheap, effective and lets you do cool renders with minimum of effort. But when you eventually want to do more serious/commercial stuff, you will have to move on to better solutions and use poser only for its content. That's just how it is.