Is the bass more detailed, do the notes start and stop quicker, has it moved more to the background of the music? For me the bass is part of the musical support for a track, it adds to the rythmn. I am referring mainly to bass guitar and drums. My setup has loads of bass detail, but the bass does not dominate and obscure the lower midrange. So to someone who likes driving rock or dance and has a setup that goes way down deep, they may think 'where has the bass gone?' as well.
How are the dynamics? Does the music still rock along or has it mellowed? If a loud section kicks in, do you really notice it, or is everything smoothed over?
I want detail and dynamics but not domination from the bass. Is that what has happened?