. . Well you aren't dreaming it, that's for sure. I added IBL and AO and the difference became quite clear. I also got nasty artifacts in the shading. Top is PPro and bottom is P7.

EDIT: Not sure i like these 'improvements.' After some more testing i also noticed the crazy amount of banding in the PPro render (compare the gradient on the thin purple box on the ground) And i tried disabling AO and still get differences. So the changes are most probably in how IBL is being done