Meh, I'm not too bothered by it, it all breaks down for me as such:
Metallica: haven't been worth a shit since 1991 and I couldn't care less to hear anymore from them. Honestly, they suck so bad at this point that even having them on the tour is a shame, considering how much they've shit on their own legacy.
Megadeth: ah fuck it, I like Megadeth. They put out some crap albums for a while, but since United Abominations on I think they've been ok to pretty good.
Slayer: best band on the entire bill, and imo they should be the headliners. I've enjoyed every album they ever released, even the more unpopular ones with diehards like "Diabolus in Musica," "God Hates Us All," "Christ Illusion," and "World Painted Blood."
Anthrax: Fuck em. I loved Anthrax with John Bush, but Belladonna's vocals just annoy me to the point of nausea. For me, the worst move they could've made was to bring him back into the fold, and I am 100% uninterested in a new album with this guy. I agree with many who say that Anthrax need to be replaced by Testament, flat out.
Overall, I wouldn't mind Metallica being booted - Testament replacing Anthrax, and a really good, aggressive band like Dew-Scented to be the opening low band on the totem pole. But that's in a perfect world....