I like the idea of parked planes at fields. Strafing planes on the ground when attacking airfields seems like it was a common part of WWII air combat, in both PTO and ETO. I'd like to see these planes "break" when they are destroyed, and burn and smoke for a brief while afterward, rather than just disappear in an explosion with no trace left afterward.
Also, a minor point - but when I see films made from other sims and they show ground operations, the films look so much more realistic and vital when there are other aircraft on the ground at the field. And when they burn and smoke long enough to make it into some shots when the field is under attack.
All gotta be balanced against the FPS loss though.