I say that the Earth team need to be in three teams: Yellow team: Cyclops as Leader; Violet team: Storm as leader; Red team: Wolverine as leader. Each team have their own authority and they can have as members anyone volunteer or chosen by leader. Headquarters updated for any new threat prevention and any team need for training, studies, and shelter. Headquarters location: yellow- Jean Grey School for Higher Learning; Violet: Muir Island; Red: Australia Old X-men Headquarter. Now the map of the territories that each team are in charge.
Yellow team: Cyclops, Sunspot, Warpath, Magma, Magik, Magneto, Aurora, Emma Frost, Three in One, Danger, Madison, Doc Nemesis, Rockslide, Moonstar, Multiple Man, Archangel, Dazzler
Let's says that the X-Men started to gather all members and non-members to fight and protect against any threat toward Earth. By doing that they form some sub-teams an additional of the main team that protect the following: Sea, Earth, Space, and Dimensional Threats. I know it sounded silly but anything can happen in the Marvel Universe.