On collisions, I've had many cases where the other plane seemed to turn into me even though I tried to avoid it. (Of course, more often I just failed to avoid it, in which case I have no complaint.) I know it's hard to collide intentionally, and I understand that if you see it you are the one who can avoid it. But I wonder about slow connects vs broadband. If a person has a slow modem, doesn't he stand a better chance to survive collisions because he will likely get his updates later?
On killshooter. This is one I really don't like, especially when the bogie you were chasing gets a prox kill on you (another AH feature I think sucks). Usually, when you have a friendly in front of you, you can simply hold your shots. But many times a friendly dives down between me and the bogie while I am shooting. And times like when I'm trying to clear someone's six or kill vulchers, I inadvertently hit the friendly. Even a single long range .303 hit, that won't bring down a bogie, will disable or kill me. These things shouldn't happen often, but probably due to Murphy's law, it seems to.
An alternative, besides no damage, that I've seen used is to allow damage to the friendly, but if you kill him (or, in the case I've seen, kill two friendlies in a day) you get penalized by not being able to load any ammo for 24 hours. It was called Personna None Gratta and helped fill the ranks of Goon and M3 drivers.