Others have (myself included) have brought up this suggestion. Other than modifying the flight model weight, since depleting ammo doesn't change the plane weight, it may be fairly simple. Then again, it may not. Since I am not in a position to know, I'll not judge whether this is something that really has to be implemented or not.
One thing I have control over is a AH2 pilots guide for the F4U planes I have been writing. Normally, I would not release a guide due to the criticism (what I call crap) from that sort of activity. With all the work the AH team has done on the F4U series, incorporating a reduced weight lower loadout "light fighter" option would compel me to deal with the unplesantness of submitting a F4U pilots guide. For whatever that is worth.
Regards,
Malta