Mishima Yukio, himself not exactly someone who was "reconciled to Japan's defeat", said several times during his career that Hirohito should have abdicated to take responsibility for Japan's war dead. Akihito was eleven years old at the time of the surrender and could easily have been groomed into a "normal" constitutional monarch like the Windsors or the Orange-Nassaus,* rather than the bizarre "completely powerless even on paper BUT icons and ideal-types to the revisionist far right BUT totally uninterested in rightist politics themselves BUT who the hell knows because the Imperial Household Agency schedules their every bathroom break anyway" chimera that the Imperial House actually ended up as. Keeping Hirohito around and executing him were not the only options!
*Possibly even with MacArthur as Regent, a post with a long, long history in Japanese court politics.
Yeah, I don't think macarthur should have been regent, that sounds too weird but thats what I would have supported as well. Plenty of other European monarchs abdicated to their sons during and after the war. Execution is what Hirohitho deserved morally speaking.
Ooh the only other issue I have with Macarthurs Japan is the permanent no military clause . This is more of a hindsight one but having a Japanese navy and army akin to the 1980 West Germany one would be an incredibly useful counterweight for Taiwan. I can understand disarming Japan vs Germany though. In Japan the main factor was definetely the military being aggressive that caused its expansionist route. Although the Wehrmacht was not even close to clean they were not the catalyst that caused German expansionism.