Lars' worst offenses as a drummer are found in his sloppy live performances. He was a decent drummer in the 80s, with one shining moment of brilliance on AFJA - which came after him taking drum lessons to expand his palette, unsurprisingly.
Lars at least had ...And Justice for All; I don't really know how, but I believe it was him and he wasn't re-recorded. Peart to me is an epitome of a black hole that completely sucks the excitement out of almost anything he touches.
I'm not talking about proficiency. He's technical alright. I just can't enjoy him at all. Next to him, all the arguably "lesser" drummers (Martin Lopez, Jaimoe, Portnoy, Andy Ward, Nicko, Shrieve and Chepito, heck Collins, back in the day...) sound so tasty, vivacious, fun. Sorry.
And my go-to prog drummer would be Bruford anyway. I wonder whether there's anyone and anything in the prog rock paradigm that would actually hold its own next ot the second incarnation of King Crimson (well, early Genesis probably would, but that's something completely different).
But yes, St. Anger is painful to hear, no arguments there.
Lars Ulrich messes up live, but he has a pretty good vision for things I think, which includes the drum sound, sometimes fans don't agree with him (St. Anger), but man, imo it's just common sense that those drums on the black album sound awesome. And yes, Bob Rock had a big part in that, but so did Lars. If a musician achieves that kind of result, he is very capable imo. And the drums on the following albums are great as well imo.
And if it's about live performance, sacred Hetfield's sometimes so embarassingly out of tune, but nobody seems to care...