Saxman,
There you go again. You have it in your head, wrongly, that the damage model in AH unfairly favors cannons. It doesn't. You somehow think that a more realistic damage model, something I'd like to see too, will lessen the the firepower difference between, say, a Spitfire Mk VIII and a P-51D. It won't. The Spitfire Mk VIII has noticeably more firepower than the P-51D and a more realistic model will not change that.
As to your anecdote, was it a bullet hole or a gaping hole blown by a cannon round? I was referring to bullet holes. If the airstreams traveling above and below the wing remain separated then lift will still be generated.