Everyone seems to forget that in the Forgotten Realms the Northern Barbarians ( I am assuming of Icewind Dale ) Are well know for their impressive strength. So adding the Man's own strength to the weight of the weapon would increase the effectiveness of the cutting edge. The Northern Barbarian tribes are Nomads so they do not stay in one place for very long, traveling with the Animal herds they hunt, so they must pack up and Carry what they have, and assuming drag large animals back to there encampment for the tribe to share in. So it would be safe to assume they may be fond of large brute force weapons such as these.
My only suggestion is to downsize the axe. I know it seems to be the new wave of having weapons way to big to be practical, but I am from an older school where I want to see something I can believe evolved to there naturally, not so fantastically that our physics are completely ignored.