So here is an idea:
A1-->C4 is the standard arena map
...
a1 b1 c1
a2 ...
...
1) There is an invulnerable earth wall between the two centre zones, B2 and B3
2) No walls can be put up between A2-A3 and C2-C3
3) That's it
Or alternatively...
1)Players start on A1 and A4
2)There is an invulnerable earth wall between the two zones, A2 and A3
3)No walls can be put up between B2-B3
Thoughts? How would this change the game? Easier to hinder, creature chokepoints and place defensive walls. Archers Watchtower of course. Seems like a fun way to mix it up until dominion custom map tiles come out.