They need to change from using the Firefly renderer IMO - very slow really for raytracing. Also they need to make sure all material channels are doing vaguely what they purport to be doing - e.g. Transluscence doesn't really seem to act like transluscence in Poser. 
Definitely better lighting with full specular options for IBL and HDRI. Some form of radiosity (not the gather node!) would be nice too.
Perhaps running Vue and Poser side-by-side is better than trying to improve everything in Poser itself - If the rigging was much improved and fully exportable to Vue to render(?).
I actually found Vue5 Infinite quite slow to render in as well, but that may have improved.

 

PoserPro2014(Sr4), Win7 x64, display units set to inches.

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