This is true, but then you run into the old competitive FPS problems of usually very limited numbers of fair/good map design, and then the game becoming almost as much about perfect map knowledge as about actually being able to move around and shoot.

This problem is somewhat alleviated, but not solved by having much larger maps.

Theoretically if someone could figure out how to make a procedural map generation aglo for a fast paced competitive shooter, this would solve the map memorization problem, but this would likely be extremely difficult to pull off.