if a song want to be popular in the general public, at least it must follow the common scale pattern or the chord progression, it can be diverted a little out of the ordinary pattern, but i has to be drew back to normal. of course DT's music is not follow this pattern, and we still love them. and i think one particular merit of DT songs is: labrie's vocal part is always traditional, no exaggeration in tones(except his high pitch voice), no distortion in voice, compared with other extreme singers, labrie's voice is gentle and aesthetic. but in the contrary DT's instrumental part is extraordinary and drastics sometimes, so this creats a beautiful contrast, and dt also follows some patterns, though the pattern they follow is not usual in its own sake.
i believe the criteria of judging a song is also varying along the years. imagine you play some famous rock song, for example megadeath's holy punishment in egypt 500 years ago, maybe they will think you are crazy and run away. the acceptance of music genre and pattern is evolving through the years, it's changing all the time.
this make me think of gustave marhler, the german composer, though he was a successful conductor in his own age, but his achievements as a composer was high questioned in his lifetime, even during many years after his death. but just like he said "my age will come", his works were finally rediscovered, marhler's symphonies are masterpieces according to the current viewpoint, but only about several decades before the opinion towards his work was totally different.
and also bach's unaccompanied cello suite NO 1, no one doubt it's a gorgeous piece, but its good musical quality can not be acknowledged in the past.
anyway,music is mysterious, music trancends language, music is beyond the description of language, so any intention of explaining or decoding music will conclude in vain.