The single best thing that could have happened to Metallica is that when James went into rehab, he didn't come back and the band split. For the following reasons:
St. Anger is painful to listen to. It's a therapy jam session. It really didn't need to be recorded. The problem you had that Bob Rock was so stoked to be playing bass for them that he forgot his duty to tell them when they were turning out turds. Booting Jason was also a mistake. Instead of acting like grown-ups and bringing him back they all behaved like children.
Death Magnetic, the production is so bad it's almost unlistenable. Lars on the documentary for it is saying something like 'yeah that's awesome'. Dude, it is not. you're deaf, get a producer who isn't a lazy stoner ####!! who just pushes all the sliders to 11.
Lulu, if this isn't just Lar's vanity project I don't know what is. James, serial Skynyrd fan, not going to be into Reed. Kirk just wants to play guitar in a band and the new bassist doesn't want to piss off the band after they just made him a millionaire.
Lars can't drum for shiteee. I mean seriously, the guy is done.
Kirk, sadly I get the impression most of the time that he'd rather be surfing.
Rob, new guy and great musician, but has no voice in the band and certainly can't do die,die,die,die,die,mother$%&#er,die anywhere near as awesomely as Jason could.
Then we have new less sweary, much more sober James. Who seems to have given over full control of the band to Lars to $%&# with. Which is a bad thing as Lars is a massive tool.
Nope the best thing that could have happened is that they ended before St. Anger with an intact legacy. James would have then been free to go and screw around making music with his buddy Pepper (which would be awesome). Really couldn't give a shiteee what Lars did and Kirk could go surfing.