To this point, if you watch films of the more lethal players, Grizz and Kazaa in particular, you can easily see what separates them from everyone else. It's their gunnery. In my humble opinion, the difference in ACM skills among the top pilots is much smaller than the difference in gunnery. Grizz and Kazaa routinely make shots, most good sticks wouldn't even attempt. Most would continue to maneuver for a higher percentage shot, and then burn more ammo to close the deal.
I doubt a scoring system will ever be able to rank that kind of skill level, and it probably needent try.
It's all encompassing in every single fighter stat. Quick killing means good hit %, less threats, less distractions, more kills. Killing enemies quickly is probably the single most important skill for MA success. There are many times I miss a shot, and because I missed a shot, was forced to fight a guy an additional 10-15 seconds, which in turn, gives another bad guy 10-15 more seconds to engage me. Had I killed him on the first shot, I would have been free to engage the 2nd bogey, and killed him. And so on and so on. Anytime my aim is off in a populated area, I am usually going to die more times than not. If it is on, you can have your way with the furball. This is one thing that dueling doesn't really take into account. Lining a guy up in a tight rolling scissor isn't the same as lining guys up in the MA from all different sorts of whacky angles the dynamics of it create.