I'm worried this thread is going to turn into a war zone, but I hope I'm wrong.... Remember this all opinions and personal preference, nothing objective here!
Anyway, as for me... despite DT being my favorite band, the only thing (imo) I've always felt was that they lacked the more 'emotional' side of song writing. Now, when I refer to being "emotional" I'm talking in regards to the type of music that really moves you emotionally, and effects you on an inner, personal level. So as I said, this is more of a subjective criticism than an objective one, because I'm sure plenty of fans are able to internally connect to their music. I definitely feel as though the band creates extremely passionate, vibrant music, but when I'm in an upset mood, or I really need a song to go to, to reflect on some of my issues, I've unfortunately rarely listened to a DT song.
I feel there are a few exceptions though, where DT does capture that inner core of songwriting:
-Space Dye Vest
-Trial of Tears
-Take Away My Pain
-Another Day
And one other thing I'd like to note is that "emotional" doesn't necessarily refer to "sad". Metallica (my original favorite band) I feel wrote so many emotional songs in the 80's that were at the same time heavy as fudge. I can put on, let's say, "Ride the Lightning" and I just 'feel' so many powerful emotions radiating from it. DT has managed to succeed at this several times, but not 'too' often for me.
ps: Go easy on me guys!