I'm truly confounded by the immediate presumption that if a game has planned DLC, that its content would have obviously been cut for that DLC. It's a dumb and naive thought process.
White March should have been released as one package, yes I'll give you that, but that doesn't preclude a developer - Obsidian or otherwise - from having good ideas during a game's initial brainstorming phase, ideas that may or may not mesh with the main campaign.
Or do people seriously prefer a game to launch, developers to get reassigned to other projects, and studio heads to only consider an expansion 6-12 months down the line? And ship a product 2 years afterward like the "Good Old Days" seemingly, nostalgically espoused here? Well, dare I say it, if you think that, then you're an idiot. The marketplace is completely different now and you're lucky to keep a consumer's attention for a few months, let alone the length of time required for a "wait and see" design approach of fifteen years past.