It is of course almost impossible to build an all-realistic damage model. And i dont think people will have it that way. Losing an elevator when flying at high speeds will make the plane pull up very hard and most likley disable the pilot. The accident with the "Galloping Gosth" is an extreme case but it shows how bad it can be to lose control surfaces.
I dont think we want to have our planes to be out of the fight as soon as the first tiny piece come off. Im afraid it will lead to more multi cannon birds trying to take all the snap shots they can hoping to rip of an elevator or something like that.
It would be great if it at least effected some part of the planes performance. I mean it just bugs the living hell out of me, to waste 25 rounds on a plane, only have one chance to make a shot, shoot half their tail off, and yet the plane can still out perform my perfectly capable undamaged plane. I agree that the plane should still be flyable. But it shouldn't be able to freaking barrel roll perfectly during a stall fight. In most planes, you shoot something like an aileron off, or flap, elevator, half wing, it makes the plane still flyable, but is very difficult to keep on fighting an enemy you are engaged with. But of course, you knock half the tail off a plane and the thing flies like nothing even happened. It is just aggravating that A. a 30mm only shoots half the tail off the plane when you have the chance to finally get a shot, B. The guy is still able to run away because I cant catch em. C. still get out maneuvered because the plane is capable of flying perfectly fine during loops and rolls. I just really think it needs to be a little more tough of flying circumstances.