Called 'marketing ploy.' Look into it.
No ****? Bungie is a business. Businesses compete against other businesses to make money. I think it's hilarious that members like you think you're clever for spotting a marketing strategy. If Bungie wants to sell Halo against another FPS, let them. The more money they make, the better they can serve their fans.
For everyone complaining about the value: $10 is not unreasonable for a map pack. If you're not willing to cough up $10 on three maps, how the hell can you be excited for the next Call of Duty? That franchise is probably the biggest offender when it comes to screwing fans out of their money. And that's speaking objectively. Subjectively, MW2's maps were total ass, and WaW's weren't much better. For those of you saying you're going to pick up Black Ops instead, go ahead, but your argument that it'll be more bang for your buck is hardly valid.
On topic: I think the maps look fine, but they don't have that typical Halo charm about them. I'd rather have a map with a great layout than a map with ornate wall and ceiling designs. Ah well, the maps look refreshing (especially because they aren't campaign ports or Halo 2 re-imaginings). I still think the expansion is worth the $10, so I'll be picking it up soon after it is released.