[andor]

longitudinal weight distribution is completely irrelevant for 4wd cars, where none of the listed advantages matter and all the disadvantages with handling do

Four-wheel-drive doesn't help when braking. Less weight on the front wheels (and thus more braking power on the rear) should make cars less likely to understeer.

[LoSboccacc]

either more weight increase grip or it doesn't, you are arguing both: the weight that you moved to the rear and allows to shift balance of brakes back comes from the front tires, reducing their grip by the same amount it increases rear tire grip

it does however increase the leverage of front tires on the car center of mass - but then that weight at the end makes getting the car straight after a corner an issue because for the same reason you get higher rotational momentum