It is definitely an interesting topic, but unfortunately, I just can't see any way of making it happen. The people pushing for this really didn't have a good grasp of how the power structure in Japan worked. The zaibatsu and the varies ministries have no reason to give up power for "direct imperial rule". Even if they did,I don't really think that Emperor Showa/Hirohito wanted to rule directly--even if he wants all that power, does he want to be responible for the mistakes that Japan makes?
I think the bottom line in this: the people arguing for a Showa Restoration thought that the Emperor had been lead astray by evil advisers--and that was exactly what they were supposed to think. The system was designed so that the Emperor could lend some prestige and legitimacy to the civil government, while the people's anger at the government would accrue to them, and not the Imperial Family. Everyone in power understood this. The system benefited both sides--why change it?