Inspired by my playing Ghost of Tsushima, what if August 15, 1281, is a bright, sunny day, and the Mongol fleet is still intact for the invasion? From my reading of the events of second invasion.... the Mongols really had no chance. The Japanese had the advantage of being defenders on an archipelago, had fortifications all over the area where the Mongols first tried to invade in 1274 (Hakata Bay, as the largest port on the Western coast of Japan, as well as being as close to Korea, was a natural choice on the part of the Mongols), and a relatively isolated, homogeneous population that decreased risk of defection or betrayal. This is too say nothing of the difficulty of amphibious warfare even in modern times, much less that of the Mongols, or the fact that Japan's geography is completely unsuitable to Mongol style tactics.
So, in summary, no kamikaze means the Mongols are just as doomed to failure.
So, in summary, no kamikaze means the Mongols are just as doomed to failure.