I realize I'm probably the only person in the world that feels this way..I did go back and listen to some of their older stuff and the local (PHX) hard rock radio station still plays some of their older stuff, but for some unknown reason it just doesn't "move" me, S/M is my fav from them. (Although I just found out my ex just bought it, so I may have to reconsider).
I'm sure if you'd had a chance to see them when they were in their "prime", it may change your mind. Most folks, after '96, got to see Metallica on the downward swing. Seeing them on the Justice tour, they played for over 2 and a half hours.
They played for pretty close to that when I saw them a few years back. Second longest set I've seen a band play (Offspring was the longest, damn near 3 hours)
I understand where 37 is coming from. I'm pretty far from a metal purist (in all honesty, metal purists are generally the most close minded music fans in existence. Change one little thing, like slow it down a little, and they all lose their little closed minds) A song can be less than 120 bpm and still be good. I have every album Metallica put out (with the exception of the Live Sh#t Binge and Purge) and to be honest the three that get spun the least are Kill em All, Ride the Lightning and St Anger. I'm of the mindset that the Black Album, Load and ReLoad are all good. I actually like that they pulled in other influences, changed up some tempos and did something other than remake Puppets again and again.