i believe the ho's have more to do with the damage models than anything else. the fact is forces around a prop and the forces going over(and under) the wings , in reality, would deflect most shots from the front.
it has more to do with using a HO as yer only acm verses one of many acm's in yer repetoire(sp.) in most cases the person using the head-on fears an extended engagment so opts out with the attempted quick kill. i personally enjoy the fight for 6 pos and will only use the HO acm if 1. its being used against me, 2. its a tough buff and the sooner i cut a wing the better, and 3. i'm completly outnumbered and need to clear the playing field a bit. those that live by the head-on, to me, don't have the security of experience in ACM.
its not just knowing an acm, its being able to putem together in a string of acm's, or compound ACM's, as i call them. ACM's in and of themselves take time to perfect, not to mention adv. ACM's, then trying to combine em..... well now yer talkin years of flight. peeps aren't interested in that in this day and age--its more about making the top of the board, than the time and effort put into making yer plane "dance." imho