I recall that the mid-wing design is somehow beneficial drag wise. If I recall right the mid-wing planes rarely use wing fairing to fuselage and this gives a hint that mid-wing plane does not really need this at all to direct or smooth the airflow near the fuselage joint.
In case of F4U there are many reasons I can think of but I don't know what was the actual reason for such solution.
One was the landing gear length versus the propeller diameter. With a mid-wing design and straight wing the landing gear would have been either in the fuselage taking space away from engine, or if it was in the wing it would have been long and weak and if not weak if would have been very heavy. E.g. FW190 has a long landing gear leg but I'm not sure if it would have qualified for carrier operations. The bend also made the wing more durable at the bend.
Stability. Wing dihedral improves stability and both downwards and upwards bending wing does improve stability and I think this is also behind the design in the Ju87.
Visibility. The bend does provide better visibility over the wing which is an important feature in a navy plane which has to do patrol duty also to spot enemy ships. This was also a useful feature in Ju87
-C+

The mid wing design by CV came about because of the Navy's requirement for a folding wing. The FM2 had folding wings, which was an early design for the Navy, but was accomplished by crewman on the deck of the carrier and it was easier to fold them down and back. This started a trend with CV as the later models of aircraft have self-folding wings which did not require assistance from deck hands.
The F4U's bent wing was designed that way for prop clearance and a number of changes were made to the oleo struts on the landing gear to relieve the bouncing effect, but was never really satisfactory. It was the only fighter that I know of which was restricted to 3 point stance landings only, as they lost many bend props and whole aircrafts with pilots trying to make a "wheel" landings.This info was passed on to me by William A. Turlelot, a CV test pilot during the late 40's and early 50's.