Sorry, man. They've got some really nifty stuff. At least you don't have a nearby seller where you stand there going "So shiny. Me want." I've even handled some of them that I had no intention of ever buying just to get a feel for their weight and balance compared to the ones I do want. My only regret is they don't let you actually swing them, though I understand it's to prevent folks who have no clue what they're doing (whereas I have something resembling a clue) from cutting their leg open and accidently chopping their friends, family or random passersby. Ah. Yeah, the weights in D&D have always been funny. I just hand-wave it as being a combination of the weight of the weapon, the scabbard and any sword belt or shoulder straps the character uses to secure it. It could also be looked at as an "effective encumberance" due to the fact that weapons tend to stick out off the body, making them more awkward to carry than something stuffed in your backpack.
I like that effecive encomberance idea - cos my claymore is only about 4lbs but moving it from place to place is a bitch
here is another weapon that we might want to make a small change to. i noticed today that the regular spear is 6lbs while the short spear is only 3lbs, the quarter staff 4lbs. now i dont think taking a foot or so wood from the shaft to make the short spear is going to drop 3lbs, maybe the spear should be 4lbs? just a thought as it seemed odd that the spear was as heavy as a bastard sword.
6lbs for a spear doesn't sound to heavy to me - you'd want to use a good hard wood for the shaft and the head might weigh from 1-2lbs