[majorfailure]

1.A penetration is not necessarily a kill in real life. And that is more likely so when we have a smaller round (even 45mm is small in tank warfare) barely penetrating. That could be fixed by implementing a more complex or a randomised damage model.
2.Pilots in Il-2 are too good at shooting, and they don't have their life at stake. They can train as many hours shooting at as many tanks they want, and fly as daring maneuvres as they want. This is not fixable IMHO. (Just as an example: I can attack a German PzIII/IV AFV with a Beaufighter, shoot it up and get away with it most of the time, and that took me some hours training and a few virtual lifes and virtual Beaufigters - and I used up some virtual Panzers, too. And I have to fly a maneuvre that in real life would be rated somthing in between suicidal and dauntless.)

P. S.: Why is it that "soft" ground targets don't blow up with the first hit (penetration)? Do they soak up damage, till a certain amount is reached? And couldn't some similar model be applied to tanks, too?