you nailed it imho.
I saw them on every tour they did since Master Of Puppets (some more then once) and you can't even compared what they were to what they are now. I would say that they completelly lost it right after the long tour for the black album. You are absolutely right about Jaymz voice and Lars drumming. Both are terrible now. I still enjoy Kirk ... and Robert.. well I just really don't care about the band since he joined so I can't really say much about him.
The thing is, for me, that they have lost so much anger and hunger live since the black album era. When you go to a metal concert you want to have your ass kicked, not scream ''hey baby'' or ''or does it feel to be alive'' ...
This was the Metallica I grew up with (I saw that show 2 days before in Montreal btw): http://www.youtube.com/watch?v=kd6e-mHddnk
look at how much Jaymz want's to fucking tear the place down as opposed to now...the attitute man, they lost a big part of that too