Gravity doesn't work the same way here. The arena is like a box rather than a flat rectangle. Movement, zones, LoS and range is in three dimensions. How is the 3Dness of the arena accomplished? It's a lot simpler and easier than you might think. All objects have height markers. The greater the number of height markers on an object, the "higher" its zone is. So even if it looks like two creatures are in the same zone on the board, if their height markers are different, then they're in different zones. Adding or removing a height marker counts as a move action into a different zone.
Flying still works the same way as in 2D mage wars. Flying creatures have a special limited form of Elusive and they have much more experience moving in three-dimensions, so they are able to dodge all melee attacks made against them by non-Flying creatures without reach.
Fractional height markers denote zone borders (.5).
So if a wall has 2 height markers and 1 half height marker, then it's overall height is 2.5.
The maximum height of any object is 3, and the minimum is 1. This excludes the outer walls of the arena, whose maximum is 3.5 and minimum is .5
The Floor and Ceiling of the Arena count as walls.
With height markers, you can fit a lot more stuff in the same arena. Make the game even bigger by combining multiple arena boards! When this happens, all corner zones remain corner zones on their individual boards. So there are 2 Arena walls in every 3d corner of every board, but all other outer walls are removed. This way you can have VERY large games. GRAND MELEE anyone? All you have to do is lineup a bunch of Arena boards together on a long table. Initiative would be shared between players with corresponding starting positions on each board. When two players with simultaneous Action Phases come within range of each other, or if any creatures they control come within range of each other, they roll for initiative between them.
If you want to include even MORE players, don't just add boards. Make the ceiling (max number of height markers per card) of the Arena Higher, so players don't have to leave their seats to reach their cards.
Cards in the same column of zones might have to be stacked to prevent overcrowding though. It is possible that this format will only work with substitute components from ACG's mage wars portability project.
What do you think?