Sounds good. I like especially #4.
Right now a Wing e.g. is damaged or not. If the fatal hit is just one 7mm shot away, you can still turn with as much G as with a completely healthy plane.
But then there should be as well some sort of damage-check. If in RL a pilot sees more holes than wing if he looks to the right, he knows he wants to go home. Slow. Without stress.
So as there is no special amount of bullets needed to rip off a wing off a certain AC, the Pilot should be able to estimate the amount of DMG already done, to act accordingly.
Maybe when you hit Ctrl-D you not only see red and green writings, but also the blend over of the RGB-Values. Best would be not a certain Percentage, because this would be too exact again. Like range-icons.
But good ideas in general.
Maybe for AH2?