Despite the general assumption that a more connected and accessible gaming community would improve the overall health of said communities, publishers are still mired in practices that continue to segregate players from one another. There's nothing more frustrating than being invested in a game to the point of buying a map pack only to find out that you won't be able to use them with your friends because they're not quite convinced its worth a purchase yet.
On top of that, the idea of forcing players to pay for the privilege of online multiplayer either through Xbox Live Gold or $10 activation codes further dice the overall community up into smaller and smaller chunks. If the next generation is going to be truly worthwhile, it's going to require a massive rethinking of how games handle the problem of access between players who have purchased different experiences.
The most obvious way to handle this would be to allow others (within limits) to join you regardless of their status as customers. This practice would simultaneously keep the community from fracturing due to purchase discrepancy, but also help encourage purchases from non-buyers who want the same experience as their friends having tried it themselves.