Need I also point out that there is a "Limited Edition" of BFBC2 which is exactly the same as the regular version except that it has those "unlocks"? So if you buy the Limited Edition you're getting the exact same thing as the regular version except that some stuff is unlocked immediately instead of you having to earn it. That's all the Limited Edition is... how can that be justified?
Because they want your money even if you buy used. That's what it boils down to. You buy the game new, you get all the additional content for free. Buy it used, you have to give EA ten bucks to access it. That's what Bad Company 2 did, and that's what Battlefield 3 is doing. I don't really see or have any issue with it, as buying the game new basically gives you free updates, something which has gone somewhat the way of the dinosaur over the last few years. And even if you buy it used, it's not like a one-time ten dollars for access to all the same additional content is exactly price-gouging.
None of the stuff that you're given access to in the "Limited Edition" is stuff you can unlock by simply playing the game. It's all extra content that you just don't get unless you pay for it either by buying new, or by buying a VIP code or whatever.
As to the potential for epic setpieces in the single-player campaign, I think this video answers that question pretty well.
http://www.youtube.com/watch?v=2SQfNwyteFM