Han Solo picks it up and uses it to cut a nice swath in the beginning of Empire Strikes Back (which is still cannon
) and he doesn't seem to struggle with it as if it was the full weight. Han Solo sure couldn't use the Force as he calls it a 'hokey religion.'
Also, the battle between Obi-Wan and Darth Vader was epic. The lack of technical skill (i.e. random gymnastics) can be attributed to the fact that they had both gotten rusty with the weapon in duels.