Larger does not always mean better. Sometimes less is more. Smaller sword swing faster, a swing from a larger blade is not 'equivalent' to multiple swings of a smaller one. It is entirely dependent on how one uses the blade and personal skill. A swing from a larger sword does not Garuntee decapitation, disembowelmemt, or amputation. Or even serious injury as odd as that is to say. I mean hell, enough leather or quilted cloth can impede a slash with a sabre. Yet far less force or blade length is needed to effectively stab someone.