Namco Bandai uses Steamworks for most of their games, Dark Souls uses GFWL but by the looks of it, it will be distributed primarily using Steam, and not that Windows something service.
1080p is fine. However around Chrismas no monitors will bre coming out that will eventually replace 1080p with higher resolutions.
4k monitors are designed and created. However desktop PC's are not quite ready for them yet. As desktops are not powerful enough to fully drive such a high end display. Thus, manufactures are waiting to release them for probably another couple years.