I'm not sure what you mean by the bad light. Personally, I think all the episodes I've watched so far look fantastic. What kind of TV do you have?
Bad light: The light is usually coming from the side leaving one side of the face high lighted and the other side of the face is rather in the dark with a very strong contrast on the face. It's where they put the light and with what intensity and focus. Often the background is very dark too. Maybe my TV is badly adjusted, although I find it more annoying with TNG than other shows on DVD/BD.
I have a 32 inch HD TV set from LG. And there, the menus are VERY small (I can't read them from 3 meters distance) while the frame is 90% empty (only background image in the center). Apparently one should have a 50 inch TV to enjoy the blu-rays.