The future addition of the Justice System, combined with the only way we can talk to friends in another faction being Cyrodiil in a bloody brawl, and how there is a lot of open area of Tamriel on the map, I've come to one conclusion:
Why not making these blanked out areas neutral? No faction controls them, and factions fighting amongst each other within the borders would be treasonous to the people of Tamriel. This way we can meet up with friends and others from different factions without having to kill each other. That and we can have some quests there that we can work together to complete. Since they are at the median between factions (with Cyro in the center), we could also have an island where all factions could go to to have large discussions or meetings. It would have to be a large island with multiple instances. We would also make it so entering another faction's area can not be done unless you are entering as a Vet in a Vet area. Otherwise, no-go. It would just be a meetup area for friends. Quests would also be abundant.
While this idea sounds rather stupid, it could work in the favor of new friends.
Argonians always and forever.