This is a good idea actually. The specific area could give a specific benefit to the Planeswalkers in the area who draw from the same mana source. In the sub-game called Planechase in MtG, your location on a plane affects your abilities and spellcasting where you get benefits and penalties. (+1 to red spells, -2 to black spells, reduce casting cost by 1 for blue, etc). In the game, you get to randomly roll what plane you are fighting on and the fight brings you from plane to plane as you are fighting
