Japanese writer and nationalist Yukio Mishima believed that Emperor Hirohito should have abdicated for his responsibility in the defeat of Japan. He was not alone, since other Japanese writers argued for the abdication of Hirohito on similar grounds. Even members of the royal family supported Hirohito's abdication.
So let's say that during the American occupation, Hirohito comes to a similar mindset and actually does abdicate the throne. This leaves a teenage Akihito as Emperor. Would General MacArthur even allow this to begin with, since he opposed the attempts to have Hirohito abdicate? And if this happened, would this affect postwar Japan in any noticeable way if the Heisei Emperor rules Japan over 40 years before he did OTL.