$10 dollars for 3 maps is the "standard" now. In Halo 2 3 maps used to cost $5 (fuck MS points btw-its just a way to say to mommy and daddy "it's only 10K points").
$3.33 per map is bullshit. It's a map.
What the fuck? That's about £2, and I buy sandwiches from shops that are over £2. I don't get 50+ uses out of a sandwich like I do out of a map for a video game, and the sandwich sure as hell didn't have the same time and effort that game developers put into making map packs. Regardless of whether or not the devs want the maps to be free, I don't think it's a massive issue that you're charged for them. Complaining about stuff like this is a total non-issue.
Same with playlists. It makes 100% sense that Bungie (or anybody for that matter) would integrate the new maps into the playlists, yes, even if they cost money. For a start, it'll make them money which is obvious and that people that have actually bought the maps can use them on the playlists. I'm totally fine with that.