The F4U prototype was a bomber, an aerial bomber. It was designed to have 30 bomblets inside of each wing to drop on enemy bomber formations.
The SB2 Helldiver was such a horrible aircraft that aircrews turned to using the SBD and fighters as an alternative to get away from using it. This is all well documented in Hugh Ambrose's book "The Pacific". One specific flaw was aileron rollers snapping on dive pull outs. The plane would enter a dive, drop ord, and on pull out the control cables on the ailerons would go slack, or in many cases, cause the plane to characteristically go inverted. Multiple aircrews were lost until one plane finally made it back to base to report what happened.
Another problem was that the landing gear lever could not be reached without loosening the shoulder straps. So pilots would take off with loose shoulder straps. If they had to ditch immediately on take-off, they would bash their head on the gunsight, usually killing them.