My guess is condensing the map rotations. They launch the PvP servers every weekend and we get combined arms as it stands for those occasions. Last I heard though, the maps were going through some maintenance and then never returned. I'd say they used up most of the available servers or whatnot and decided to make it a weekend thing. This would allow for a new playlist which is apparently a grimoire card already called Inferno. I still haven't seen it, but the description of it is awesome. We'll see though.