it would be interesting if players could choose to customise the dice in their game - they could choose the "dice" to have 5-8 sides (or more) to skew the game play either more in favor of defense (fewer sided "dice") or attack (larger variables on the "dice").
The actual combat mechanics would remain the same, attacker gets 3 dice defender 2, defender wins on a draw.
You'd need to feature the sides of the dice prominently in the "join game" menu so that players knew what they were getting into when signing up.
This wouldn't take that much coding to implement and it would be something significantly new for people to experiment with. I think it would work well with the nuclear games.