I think that there should be a point/money system, where you can buy items to improve gameplay. Ideas on items - Increased luck (for period of time), Ranged attack (Can attack 1 or 2 spaces ahead)
They should make it so you get units that other players have when they return them. its just so annoying when you go to kill someone, then they cash in there cards and quit.
There is always that 1 player who holds a grudge against you, why don't people just let their emotions and have fun? its a game people, not a way of unleashing your rage.