The
decision made with the Corsair was to reduce the Interference Drag by
acheiving, as much as possible, a wing-fuselage joint perpendicular to
the fuselage, (The inverted gull wing) with a minimum of filleting,
thus reducing Parasite Drag.

Actually, the major driver for the inverted gull was finding a way to make
clearance for the HUGE prop so runways and carrier decks didn't get chopped up.
All the drag reduction trades and benefits were a natural fall out of the
design.

Keep in mind, the wings could have been put have been put at the 90 and 270
position and achieved the same benefit. But the prop would have went chop,
chop. Also, the inverted gull was not the best actor in stability and control.
I am not saying that ultimately it was not good, but even then the spins and
the recoveries were an occurence to behold.