For me, Metallica and Lars was a reason (the main reason I think) I started to play metal-oriented music with my bands in the late 90's. I unfortunately was not old enough to hear them in their prime years (80's). I don't hate the guy, I respect him a lot for what he has accomplished, and their first 4 albums (maybe 5, but it's a stretch) will always stick with me. And as you guys have said, he was sort of a pioneer in making up the thrash metal drumming style, he was really fast back then. For me, the main reason why I don't like him today, is because of his current ability (or in better words, lack off). I don't care so much about the whole Napster thing, or that he sometimes can be a bit of an a** in interviews. To me, it's just the way he plays live (nowadays, not back then), which in my opinion gives you the best impression of how he is as a drummer (you can do anything in the studio, cut and paste for hours and with enough time and money, any drummer will sound good). I stopped going to Metallica shows maybe 10 years ago, after he was well into the decline. It gives me more frustration than happyness to see them play and to me they are nothing more than a novelty act right now... It's just so un-inspiring to listen to, same boring fills (or just basic snare hits instead), no ride cymbal, hi-hats way too open to sound good, timing is all over the place, doublebass sloppyness etc. The list goes on. To me, it's borderline insulting for all those people coming to hear you play, even if most of them don't seem to care. At least when you get that big, you should try to do/be the best you can (in my opinion). That is his main job.
You might say that it's simply because todays music are so much more evolved, that Metallica simply sound outdated compared to other metal acts today, but I will disagree with that. 80's style thrash metal still can sound great, if you maintain/evolve the skillset aquired to play that style. Look at Testament, Slayer, Exodus, Kreator etc. These guys all started at the same time Metallica did, they're the same age, but still has evolved and play this type of music to perfection, some even sounding better than before, to my ears. Metallica just became lazy (in my opinion), and Lars in particular. Sure, they are not playing only thrash metal anymore, but they still play a lot of the old songs that IS thrash metal, and when the skill is lacking to do that, it doesn't sound right at all.
The last show I think Lars did pretty good, was the S&M show right before the year 2000. Seems like he practiced quite a bit at that time, to keep in time with the orchestra, and he looked to me pretty solid during that show. After that, every liveshow I've seen has been a letdown. Sad but true...(no pun intended).