I was at the William Wallace Memorial in Sterling Scotland in June of 1998.
They have a replica of his sword that you can hold and swing around... it is almost 5 1/2 FEET long and weighs about 30 pounds. They mostly set the sword in place and let the knights impale themselves on it as they charged. The battle at Sterling is what first made Wallace famous... a narrow bridge over the river - nobody could get by him.
That is his actual sword in the case... from 1305.
It's hilt is wrapped in leather - kinda. He had a habit of cutting strips of flesh from his slain enemies and wrapping it around his sword handle.
William Wallace was something like 6'5"... a giant in his day.
Mel Gibson is 5'9"... not exactly comparable!
An admirer of the movie carved a likeness of Mel as Wallace out of a log... it was on display in the parking lot when I was there... it heard that later it was torched by an outraged Wallace supporter.
I can guarantee you that the actual sword did not weigh anywhere near 30 pounds. Swords of that size usually weigh in the neighborhood of 4 to 6 pounds. It would take a large, strong man to wield it effectively. A soldier trained in the use of such a weapon would be able to swing it with amazing speed and devastating impact. The replica may well weigh 30 pounds as many people who make replicas have no idea of what real swords used in the middle ages actually weighed. Anyone who tried to use a 30 pound sword in combat would have been quickly cut to pieces.
Anyone interested in the characteristics and handling of real medieval and renaissance swords should check out the Association for Renaissance Martial Arts. There is lots of data at their web site.