A lot of places in the environments seem under-lit, especially if you turn off the camera light. It would be nice to be able to add light nodes, or otherwise be able to control the lighting of the environment.

It would also be nice to have a brightness slider (gamma slider?) in the preferences menu.

Or, heck, a possible quick and easy way to address any lighting problems might be to put a "brightness" slider in the "scene" menu in the interaction editor, so the creator of an interaction can choose to boost the lighting of the scene if they've put the characters in an under-lit area.