(hope they aren't rhetorical questions)
"average short sword have weighed"-- About 1-3 lbs, depending on the period. A gladius weighed in around the 1-5 to 2lb range, and may have been 20-28 inches in length.
A heavy single edged chopping short sword known as a falchion might weigh as much as 3 lbs and be 20-30 inches. I would class any khuk over 18 inches as a falchion. [[In the bronze age, all chopping weapons like the khopsh (the ancient predecessor of the Khukuri) Were short and heavy, for close combat. for long range the spear was the master.]
"average Medievel battle swords one or two handed"--One handers are typically 30-40 inches in length overall, with a weight roughly 2-3 lbs. Hand-and-a-half (bastard) swords were about 40-48 inches OA, with a weight aroud 3-4 lbs. Two handers of all types ranged about 48-72 inches overall, and weighed ideally in the 6-7 lb range. Any sword bigger or heavier was most likely a 'bearing sword' the big bro of all parade swords.
"Scottish Claymores...historically accurate...9+ lbs!"--If it ain't scottish its crap! Seriously, tho. Who would wanna swing something that heavy around? see my coment on bearing swords above. 9lbs is unrealistic. They could've slimmed punds off that one with a distal taper, but most likely it was made by stock removal, not forging. Been readin' Museum Replicas catalogue again Rob??
"Am I that much weaker than my ancestors?!" You, maybe (heeeh!) Naw, just sounds cooler to sell someone a 7pound Conan sword than a really slim, 'weaponized' sword.
For instance, certain websites selling "Viking" swords say that they were big crushing barbarian swords. The site sells 6-7pound viking swords (yeow!). The replica I have was hand-made to the specs of an actual sword from the period, dredged from the Thames. It is only 34 inches long, and weighs only 1Kg (2.2 lbs)! Which one do you wanna swing multiple times if your job is to hack stuff with this tool? The answer was obvious to our ancestors.
"Seems like the key to handling any of these one handed weapons with agility is as much a matter of forearm/wrist strength as dexterity."
>>Agility is always a key factor in such contests. Fighting in armor with sword and shield means running in armor, sword and shield. Very Areobic. Don't try it if you have bad knees.
You also learn how to run backwards as fast as forwards. This style of fight is not static, as shown in movies. you gotta keep working your angles, get your opponent off of his line of the attack, while getting him in your line. It's very much a dance of ranges, angles, in, out, thru...
Keith
En Ferro Veritas
NOTE: Discussion of sword weights and lengths is assumed to be European. Some Asian weapons may be lighter or heavier.