I'd say that's pretty much what it is with Assasins Creed 2. We will have to get used to that - both DA:O and AC2 rely on DLC, with some of it going live on first day. Bioshock is aiming at something similar. Even Epic did the same - hence the Flashback mappack. This is a strategy to fight with used game sales and pirated copies. And actually I'll prefer it be that way instead of copy protections, as long as Microsoft will stop treating customers in countries w/out LIVE as 2nd rate and will stop stripping local copies the DLC codes.
Its flat out a crappy thing to do. It doesn't fight pirates (because, surprisingly, they pirate the DLC) so it's no "alternative" to copy protection. If you want to make it so that your game can't be resold, make a deal with Valve that they need to activate via Steam to play. But if you're going to sell things in physical form, it's a shady, shady move to remove portions of the game and say nuh uh, you don't get to play because you didn't buy it the right way.
~Jason