Amsci,
Sorry, aerodynamic is not really my speciality.
I read somewhere that dihedral increases stability and anhedral maneouvrability. In the case of the 453MW, both seem to combine each other, between center and external sections.
As for the Vought F4U Corsair, one of the avantages could have been the reduction of the main landing gear size, but this aircraft was equiped with a tandem monotrace main landing gear...
So???
But I am sure some members of the group will give us the definitive answer.
All the best,