I got my copy at Walmart this morning and they specifically told me, even out of the plastic, as long as you have a receit they will swap out the damaged product for a new product with the same name. So no you couldn't return it to get a different game, but with your sales receit you should be able to swap it for another copy.
I too am having the "halo 4 servers are not available. Please try again later. Matchmaking has switched to using the default playlist". I went to join a friends party/game and it said "could not join party queue". However after that a screen kept repeatedly flashing on and off with the original "could not join party queue" in the background that said trying to join. It made it so I wasn't able to go forward, or backward to any menus, I had to shut off my xbox. This is a huge bummer considering I prepped for 4 hrs in campaign and this is my only day off for awhile. I hope this gets fixed soon.