Weapons from japanese cartoons are also exaggerations of real weapons. Where do you draw the line? For me, a fantasy weapon is a weapon that is unfit for real combat. I ask you again: Why do you think the real war cleavers were not 120cm long?
Also, you don't seem to know what balance means. It means two things: A) that the overall weight of the sword is not too high and B) that the center of mass is close to the handle, not the tip. It is simply not possible to make a weapon like the cleaver balanced. And to wield such a weapon one-handed...forget it.
But again, realism is irrelevant. What is relevant is balance compared to other 2h weapons, and, as I have said, and as you seem to disagree on, the cleaver does fine in this respect.