I think it would be useful for the line of sight behavior to have a range option. It would be helpful in the cases where you don't want an enemy to see you from all across the level. Of course, I'd think it would be even cooler if you could have a forward range and a backward range, basically so enemies could detect stuff farther in front of them than behind them. Any chance this could be added?
I would do this using an x.y comparison between the enemy and the player. I guess it would make it easier though if there was a range option so you wouldn't have to do this for every instance of something.