I like the background mechanic too but what I really want is a group background mechanic so that groups get a bonus for creating a real team instead of a bunch of individual loners. I can't tell you how much that would help me as a DM.
You might want to check out the Primal Power preview, with tribal feats. These feats provide a variable amount of bonus depending on how many people in the group have them, so the benefit progression to the group is geometric--i.e., one person gets +1, two people get +2 each, 3 people get +3 each, etc.