Multi player gaming on FPS or any game for that matter on XBOX or PS3 has been an issue for the console division since we came about in the bowels of TOG's Forum.
Several attempts have been made all unsuccessfully to get TOG's casual gamers to come together and play. Unfortunately it hasn't lasted long.
I put it down to the fact:
1. Consoles are still seen as the poor cousin to the PC when playing online multiplayer games.
2. People seem to play games on the consoles to fill in the time between releases on the PC.
3. Game releases on consoles seem to outweigh those on PC when you take into account kids games. ie. to much variety.
4. Conflicting usage of the console between the parents and kids. ie. one machine for the whole family.
Their isn't the commitment to playing a single game for to long.
Another perceived problem could be the leadership. All have tried to invigorate the division but in time the job was to much work or to hard and failed. I think for the reasons above. Some have the title but have so much happening in the RL that they can't fully commit to organising the division. Some have gone overboard with their commitment to the division resulting in personal issues which resulted in them standing down.
I know that doesn't truly answer your question and would seem to be a cop out. Sorry.
If anyone has any answers I myself would be happy to hear them and try to support what changes need to be made.