Hearing Lars STILL defending that mastering job is worrying. I'm sorry, Lars, I really liked the album but it sounds horrible, and you deserve better. Even if it doesn't sound bad to you, it sounds bad to a lot of people. And I guarantee you that the Guitar Hero version will not detract from your listening experience (if you can't hear the distortion on DM you can only slightly hear), while improving that of a lot of people. It's seriously not that hard to admit that you were wrong about the production and that there is objectively something wrong with it. I guarantee you that every one of your fans will either a) not care or b) become far more likely to buy your next album if you say that.
But yeah, if Lars says there are two names and that they're not surprising, the names are probably Bob Rock and Rick Rubin. Given that Bob Rock produced The Black Album, which is probably their best sounding album, and Rubin produced Death Magnetic which was totally botched from an audio standpoint, I'll definitely take Bob Rock. And the songwriting is already in progress, so from that standpoint it's going to be what it's going to be, for better or worse. Personally, like Blob said, I'm rather hoping for an album of mostly 5-6 minute songs, which I think they still may be able to pull off.