“In every episode from 4,5 and 6, I kept improving the sword fighting because the assumption was Luke was getting to be a better fighter, he was learning more. But at the same time he wasn’t being trained as an original Jedi would’ve been trained.
In Empire strikes back it’s the first time that the antagonist and protagonist actually fight each other so that it is a very big fight and Luke now has become proficient enough to face Darth Vader. So it’s a slightly one sided sword fight where Vader has the advantage over him.
He was fighting the man who he thought was his bitter enemy. He was fighting as hard as he could. He was fighting the man who killed his father, Obi Wan Kenobi, personified evil in the universe. Then in the next fight it’s more of an equal competition. Centred on more of the emotion than the fight itself.
video of rage Luke battering Vader
Then when we move to the prequels, where there were Jedi in their full flower and fighting as they were in the past. Then we had to make the fights much much faster, much more sophisticated and much more aggressive in the way they fought.
video of TPM Maul vs Obi Wan and Qui Gon
And we continued that.
video of AOTC Anakin vs Dooku
The fights actually become much more ferocious then say the ones in 4,5 and 6."
video of Yoda vs Dooku
-Birth of a Lightsaber by George Lucas