I also agree with you. Having played all 3, GK2 is my favorite (with the first being very close behind). However, as far as GK3 goes, I was kinda disappointed. It was still a good story, but it didn't seem as well thought out as the other two. Also, Gabriel's character was rather bland in the third one, whereas I really liked him in the first two. It was still a fun game to play, but there was a definate drop-off from the first two games IMO.
JankyToe: Color me stubborn then, 'cos I still think GB3 should have been FMV, with Dean Erickson reprising his role as Gabriel Knight. I really enjoyed his performance (alongside Von Glower and Grace), but I guess I'm in the minority here...
Don't get me wrong though, I still enjoyed GB3.