I think it all depends. Depends very much on the program material, indeed. For movies, I usually settle with the trim level set by Audyssey, but I can defend the OP's father whenever it comes to 2.0 ch stereo music (redbook CDs), especially some oldies that do lack bass in the recording. In my experience I did have to increase the sub trim in the AVR to +10 dB or even to +12 dB, and it was still not enough. YMMV.
Yes, agreed. See my post to Beast. I always forget that people use their theater systems for music.