Luthier, there's a factor that has always been not taken into account by the sim creators, the only example that I can think of where the thing was actually simulated was the now ancient but at the time revolutionary "Fighter Squadron: The Screamin' Demons Over Europe".
Aeroplane structures are elastic: you can see wings flexing, fluttering or bending before breaking or on high G stress. A fuselage gets torn and deformed after a heavy landing or a crash landing.
Will we ever see anything like this? Pulling too many Gs and trying to make it home with a bent wing, hoping that the fatigue won't give it the final hit?

Another thing is the attention to the shock absorbers response: IL-2 planes are all too stiff on their landing gears, while in real life the suspensions play an important role, especially in the response on the ground and at landing.. a careful simuation of that and maybe an suspension failure would be very appropriate.