If the weight bothers you, you shouldn't be using claymores. A katana would probably serve you much better. I prefer daggers, kitchen knives, and scimitars. Besides the lighter weight, they are easier to fight with if you have low skills.
I'm pretty sure the only characters in FF7 that used giant swords were either huge monsters, or enhanced by that mako exposure program, like the members of SOLDIER, who were the only intended users of the swords. It's as if the guy in the video tried to make "Excalibur" to prove how it isn't magical, or that Surtr could never destroy the world by throwing a shiny sword. On the otherhand, I guess there are a lot people that can't tell the difference between fiction and reality when it comes to subjects that are so far removed from their lives, (understandably). He probably satisfied more than one person's curiosity. Still, it looks like he wanted to prove his own theory, rather than disprove a theory.
I'm playing a Claymore, and I'm a sucker for SP roleplay, so~
Besides, the weight wasn't a problem, and I was getting 2-3 hit kills on things several levels higher when it was bronze, it's just that diamond is the second heaviest material type. Almost everything but adamantium would be light enough to not push me over the limit.
RE: the video: Damn you, I just spent close to an hour watching a bunch of his other stuff.
And I think the point he made, particularly with the Dragonslayer video, is that it is technically
possible for someone to use a sword that size, but that they'd have to have massive upper body, back, and leg strength to be able to use it for more than a minute or two, much less develop anything resembling an actual style beyond "overhead swing overhead swing overhead swing".