It shouldn't give straight points for hitting doors, but at the end of each round, "Awards" should be given to:
-The attacker that did the most damage to gates/doors that round
-The attacker that opened gates the most that round
-The attacker AND defender that did the most damage within a certain radius of the flag
etc
These awards should be pretty minor, on the order of an extra XP/gold tick. But it would add a fun meta-game for some people.