Type of improvement:
Increase the level of upward lift of the wings and make the difference of "loss of airlift" from one side (e.g. when a wing is missing) more severe.
Explanation of proposals:
If you lose a tip of the wing, the plane is easily controllable with the remaining aileron.
In reality this should be much more difficult.
Picture #1. Wingtip+aileron is missing, no problem to control the airplane and land it. This is too easy.
Picture #2 & #3
Half of the wing neatly sawn off. Airplane is at the limit and difficult to control. But it should be impossible to controll this damage at all as the good wing would produce so much lift that it would cause the plane to enter an uncontrollable roll which could not be recovered by the compensation from the remaining aileron.
Benefits:
Increase realistic response of the plane.