Now all we would have to do is decide where the portals would be. Or decide if a universe has more then one door to the same place. If the gates are in one spot though it would make it a nice strategic position. So I'd be in favor of the former. (though Nexus is probably unique in that it has a gate for each realm)

Maybe have a faction that controls their nexus gate allows all their ships to use it, for people who want to bring they large ass ships or large ass selves to another realm.

Mystique's gate would be prefect if it's on the Mystan moon. Gives a reason to go there if nothing else.