It seems to me that the black album was a turning point. Not as complex song-wise, more straightforward during recording, and more commercial production values than previous albums. Still, it's much better than anything they've put out since.
I remember reading an interview with Kirk right around the black album, and he said that he had never played many of the solos recorded on the older albums, they were stuck together, sometimes note-by-note, onto the master track. He'd be called in to record a 1/16-second three-note pull-off so the engineer could tape it into a gap. Ouch. In the "Year and a Half" video, you can see that the recording process was much more natural for the black album.
As for Bob Rock's (over)production, at least it was nice to finally HEAR Newsted's bass. And hey, now that Jason's gone they should just get Flemming R to produce again and nobody will notice!
