Yea, you're right about the "plastic doll quality", but that goes back to just learning what you need to adjust in Carrara.  I've been working mainly in Animation Master lately, but I remember I always had to make a few adjustments in C5Pro after importing a Poser figure if I was doing a close up still, which wasn't often.  I believe I had to lower  'shininess' and also fiddle with bump.  I'm sure there are others who do more Poser stills than I who can shed more light on the topic.