Even the music is flat. Compare that to TOS which is positively melodramatic. And that's why the predominant experience while watching a TNG era show is one of, at best, mild amusement, but not the engrossing feeling of watching, let's say, City on the Edge of Forever, or Balance of Terror.
Totally agree, and it was one of the biggest problems I had with TNG. It got even worse when Berman fired Ron Jones, who wrote scores with actual melodies and character themes, including the memorable score for Best of Both Worlds. Apparently Berman didn't like his style, preferring the music to be less obtrusive. I wonder if part of Berman's problem was Jones previously working with Disney; maybe he felt Jones wrote "Mickey Mouse music." TOS' music were an important part of its style, with brassy, exciting scores by Fred Steiner, Gerald Fried, and others.