I'm all ears, I hate wasting time.
Ok, I honestly didn't expect that response...
If you model collision "fault" based on speed alone, it becomes an unbalancing factor and will have effect far beyond the fights where collisions occur.
If you decide that collisions are the "fault of the fast guy", you'll destroy any chances of "fair" close fighting between a fast plane type and a plane that's inherently slower than that. An extreme example would be between a P51 or 262 and a Spit1. If the P51 pilot knows his stuff, he'll seldom (if ever) be as slow as his target, so he'd have a much better chance at being found "at fault" simply because of the plane he chose to fly. And if the pilot of the slower plane type
knows that he'll be held faultless for any collision that occurs (simply because he's slower) why would he avoid colliding? What would keep him from using collisions to his advantage? This would put an unfair responsibility to avoid colliding on the faster pilot, while removing that responsibility for the slower one.
Conversely, if collisions were always the "fault of the slow guy" imagine how reckless that high P51 could be when he dives in on your slower plane... He'd have no fear of colliding, because it would always be the slower guys fault, right?
Amongst identical plane fights, why should the guy who's a few mph faster than the other be at fault? Why should the guy who's a few mph slower be to blame? Energy conservation is a deciding factor in fights, but in the case of collisions it would reward the guy with less energy.
A collision model based on speed would shift fights further away from reality.
You cannot place blame on a pilot because they have a different speed than someone else. You also cannot place blame based on angle of intersect, or even based on who's airplane entered someone else, or one what part of a plane entered what part of the others.