[quote=@rextremendum]
That sounds good. Have each player play as the plainswalker corrosponding to a particular plane, then have some crazy batshit magic bullshit chuck them, and a bunch others, together, and have every one work things out and decide what to do for their particular plain
[/quote]

These would have to be the godlike Planeswalkers from before the Mending.

[quote=@Smiter19]
So the Planeswalkers would be commanders and or the leaders of the nation? The nations would be founded within different dimensions? I'm not entirely positive about this part, but can Planeswalkers open portal/gateways to another dimension?
[/quote]

Only for themselves, generally.