The collision system in AH is the only viable collision system given the time delay inherent in the internet.
I just don't see how you guys have so much trouble with killshooter and collisions. I've been a subscriber since v1.03 and on Sunday last I had my fourth aircraft loss from killshooter. I'm averaging less than two killshooter deaths per year. I collide more often, but it doesn't bother me at all that only I get penalized for my collisions, after all it was on my FE and so only I could see the collision and try to avoid it.
Imagine if you died due to colliding with an aircraft that was 250 yards away from you on your FE. That is what it would look like 50% of the time if both people died when one FE reported a collision. That would frusterate me as I would have died due to something I could not have avoided and had no way of knowing I needed to avoid.
If both FEs must see the collision for the collision to occur there will essentially be no collisions anymore.
Tactics to be derived from this involve things like intentionally flying through the target aircraft while firing as it is impossible to miss from one foot away from the target. This is not a small change and it would not be rare.
Another effect would be the switch to free form manuvering without regard to the proximity of your airframe to the enemies airframe. It would remove one of things that a combat pilot in a close dogfight needed to track from the game.
This kind of change in tactics essentially destroys any and all simulation of real world tactics. The rules have been changed so much that it is no longer a simulation of WWII air combat tactics.
Personally I have no interest in flying in an environment in which the need to avoid collisions is not part of the tactics used.
Killshooter is needed to enforce a semblance of fire disappline. It isn't perfect by anymeans, but at least it forces people to not shoot through their team mates to get kills in a manner totally foreign to WWII air combat.
Keep your SA up in regards to both friendlies and enemies positions and likely headings. It helps avoind both collisions and killshooter, even when a dweeb cuts in front of you.