Corn stands were better following other crops. Rotations reduce insects. This year corn rootworm beetles are high on corn following corn and corn rootworm damage is common- even on some treated fields. Rotations increase drought tolerance. I've seen several examples where corn following corn was rolled due to drought while corn following sod in the adjacent field was not.
Crop rotations increase crop diversity.
Small grains did well this year and soybeans may benefit from late rains. Having some of these crops on the farm helps out in drought years. Rotations reduce weeds. Dandelions in alfalfa and perennials in no-till corn seemed especially bad this year. Rotation is a good cure for these problems.