I'm thinking too much like Dynasty Warriors whilst your thinking the battle of Hastings. I had always imagined the damage from a Lightsaber came from the plasma blade not the effort put in by the combatant to hit hard with it. But I do take your point, if you're not able to apply enough force (not The Force) to your attack swing then your not going to do as much damage.
It's not really even about how much force you put behind it, but whether or not you can do more than just graze them with your spinning weapons. Rolling to hit is an oversimplification of what it takes to hit and do damage to a person with a weapon. After all missing with the roll doesn't mean you failed to hit. You can interpret a miss as a glancing blow, sliding off the characters armor and what not. A successful hit means you not only applied enough force to the hit to do damage but that you also struck them in a vital spot that does real harm to the body.
My argument is less about the source of the damage and more about the technique and whether you can land a solid enough blow to do any harm to a person. After all both The Clone Wars and Rebels feature lightsabre battles where the characters are hit with a glancing blow from the lightsabre or it slides off their armor or etc etc .....