I would have been totally willing to buy the idea that Zorba had become mad with power over just a few months if they didn't go to the retcon well. He says they *elected him* in that middle story where he's all reasonable and sane, if angry. Then in the Fall of Zorba bit, the woman says King Zorba instituted martial law before the elections began. That contradiction would have made me think that the woman and her son were actors pre-arranged by Doom to trick the Fantastic Four, if Zorba hadn't turned out to be irredeemably insane when the panels switched to the palace.
They were trying waaay too hard to make Zorba unambiguously Evil(tm) to excuse the return of Doom. Shouldn't have to make an incompetent tool into a murderous nutbag just to make Doom look better by comparison.