Originally Posted by SouthFLpix

As long as your pedals have enough surface area you don't need an especially stiff shoe. The reason you need stiff shoes with SPD pedals is because the actual platform that you stand on is smaller then a Zippo lighter. That means that without super stiff shoes that small piece of metal would push very hard against the balls of your feet and cause severe pain. So to counteract this you need incredibly stiff shoes to spread the load from a very small area (the SPD pedal) to a larger surface area that your foot can comfortably rest on (the sole of a cycling shoe).

With a large pedal, the stiffness of your shoes becomes irrelevant.