a "paratrooper" or "bomb" card
Many of the games i play have everybody set themselves up with all of their armies on their borders and all of the territories in between with 1 army. I think a para-trooper card where you could drop a select number of armies to take over a territory in the middle of your opponenents land would be good, or a bomb that you could use to reck some havoc in the territories that everyone seems to ignore. Heck call it a "rebellion" card and have it so you can overtake one of your opponents territories
Bomb cards have now been implemented as a member-only feature. It halves the amount of armies on an adjacent territory.
That would be cool...though I think it'd need to be a special game of some sort, like multiattack is