One of my demands (sorry, one thing I would like to see) is a map which is cut by a large chasm; it doesn't have to be straight. This is an area of the sphere which is still under construction. The energy from the sun blasts through this split in the sphere. The only way to get ground units across is to transport them, but the heat from the sun causes damage to anything crossing. The only way to get a large force across and assault the enemy is by building a bridge across this gap. Who ever places the first bridge has the advantage; but if your assault is unsuccessful the enemy can swarm across to counter-attack.
That would be pretty epic.