When you battle it out and one stalls and crashes its your achievement, so i think the message is in order. Getting the kill for the better pilot, eaven if hes better at keeping his bird in the air.
When you are in a one on one and the other one prefers to crash instead of fighting you should get it too, because if not the people could just crash when the tide turns against them, if there is no kill awarded it should also be no death.... which would be an easy way to rtb without dieing or hurting score.
When one crashes and the otherone is close, but has nothing to do with it you are right and it shouldnt be awarded. But how would you determine that and decide weather he crashed or it was a "maneuver kill"?
I beleave removing the maneuver kill would be disappointing, at least for me. I often pull close to the ground split S where the enemy follows and lawndarts.