The easiest solution would to let NA admins control the NA2 map rotation, and they would mostly pick smaller maps suitable for our low population. Right now, the rotation is controlled by people that don't even play on the server.
The other solution would be the population-based respawn timer idea, but I don't know how difficult that is to implement.
A few nights ago I counted consecutive wins by the attackers; it was over 15 when I stopped counting. Unless the defense team is totally stacked, or the stars align and more than 40 people are playing, it's a near-guaranteed win for attackers.