Maybe they wanted it to focus more on the political/oppression aspects of it, I don't know. I think the way it was done worked; you got a striking visual contrast between District 12 and the Capitol, between oppressed poverty and garish excess.

My thinking on this really was, you *have* to think of this as Part 1 of 3. And there are probably a lot of things that don't quite make sense or matter now that will matter a lot more once you watch all three movies.