[quote name='Corvin']Re-read the press release. There is exclusive content on this new version. It screws everyone that already supported the game and made it a hit. All the other games you mention didn't do anything of the like.[/QUOTE]
No, it doesn't "screw" anyone over. This is a little like buying a copy of, say, Dark Side of the Moon and then getting offended when, a year later, there's a rerelease with a few demos added to the end of the album. Yeah, the demos might be nice...but it doesn't change the fact that the core product is the same.
When you buy a game, you buy it for the game - as in, what's on the disc when you purchase it. You're never guaranteed DLC, and you're never guaranteed that there won't be a newer, better version of the game released down the road (like the Mass Effect bonus disc, or Gears of War with all of the formerly DLC maps included). Game of the Year style rereleases usually have DLC or new content that the first release didn't include, but those have existed for a few decades now and I don't see anyone boycotting publishers over it.
Bottom line: it's one mission that's being included in an attempt to help generate sales and to give people a little bit of incentive not to go to GameStop and get the cheaper, used copy of the game.
Yes, it might be DLC down the line...but even if it's not, your life won't be a hollow empty shell without it, and the fact remains that up until now, you enjoyed the game without this content. I can play Arkham Asylum without the Joker levels, and I can play Assassin's Creed 2 without the GameStop preorder level. Guess what? They'll still be fun! Ideally, all content would exist for all consoles and all editions of a game...but that's not how the industry works these days, and if I don't give LucasArts my $20 that won't change anything.