I don't understand why people want Playtonic to immediately get working on the sequel if they feel they have more ideas for this game that they couldn't afford to put in the base release. A sequel will take years (and might not even get off the ground unless the first game did well enough, which DLC helps support), while DLC is new content that'll come out much sooner. I love DLC, I love new content and I want it as soon as possible. I'm not getting any younger here.
I get why people hate DLC nickel-and-diming schemes from big money hungry companies but when it's a company that makes stuff you like and that you want to support it's really just another way for them to provide you with content and another way for you to provide them with support.
Personally, even as a backer, I still plan to purchase the game and all DLC at the normal price.