This is tangentially related to this topic, but it's interesting.
I was at a panel discussion of WWII pilots last weekend at the Museum of Flight in Seattle. One of the panelists was Ralph Foltz of VF-15 (flew Hellcats from USS Essex, 5 kills). He said that pilots were sometimes told that, if they had run out of ammo, they should try to take the tail off their adversary using their props. He was in a fight once down on the deck where he saw a fellow Hellcat chasing a Zero go for that maneuver. "The Hellcat got closer and closer to the Zero and then took its tail off. The Zero went right into the water, and so did the Hellcat."
I think collisions should be part of the game, and I think they work about as well as you can manage with network delays (i.e., you get a collision if it looks like a collision from your view).
(Also in the panel discussion were Ralph Jenkins, P-47 pilot in 9th AF, 4 air-to-air kills, lots and lots of ground attack, train busting, attacking GV's, Panzer groups, etc., including what he thought at the time might have been the attack on Rommel's staff car; Harry Ferrier, VT-8 in Battle of Midway, TBF Avenger radioman/gunner on that one TBF that made it back heavily damaged to Midway; and Kelly Gross, P-51 pilot, 6 kills including one Me 262, and including being shot down by an infantryman's rifle bullet once in a P-51 but surviving having 2 cylinders shot out of his engine by a 20 mm cannon round when earlier he flew P-47's and not even knowing he was hit -- not even a rough-running engine, he said.)