I think it's because of the learning curve. When I started to play, I was terrible in melee fights. Even when I hit, I did poor damage. Now that I'm used to the gameplay, I started a new game and with my new lvl 3 caracter I hit regularly and do frequently 30 DAM on my targets. This is about 40% of the damage I can do with a pistol. All is in the angle of attack and the speed. High strength and Power strike are essential. I know that eventually with a good sword and a good horse I will chop my way to glory!
But anyway, it's a game based on the fire and sword - Deluge novels, and there's no full plated two handers in these. Dashing hussars and crazy cossacks rule! There's even a comic relief character in one of these novels who swore to stay a virgin until he could chop the heads of three heathens in one blow. It's a symbol; the melee maniac can't propagate in this new world.
Also, the 1640-1660 period was the end of the landsknecht-pikemen-tercio era. The Swedes and the Frenchs destroyed their melee prone enemies with small units of musketeers and lightning fast cavalry. Reiters, Hakkapellita, dragoons and dashing hussars for the win!