Here's why the OT saber fights are far superior (long read)

tl;dr-last paragraph.

The saber fights were better in the OT simply because they were the products of competent cinema. When viewed in overall context, the battles were much more relevant and impactful in the original films because they were a means to an end, not the end in and of themselves.

All the fights in the OT held narrative gravitas. They were the culmination and climax of brilliantly escalated tension. For example, look at Luke against Vader in V....that fight was amazing because Luke knew he was going into a losing battle. He knew he wasn’t ready. He knew he was walking into a trap that would likely result in his death, yet he went for his friends. Everything he had been told by Obi; the belief that Vader had murdered his father, his training with Yoda, watching Obi get murdered in front of him. On top of this you had Vader’s reveal. Or in VI. Luke attempting to save his father, Vader’s sacrifice and ultimate redemption borne out of love for his son seen through the greatest of evils. I’ll admit that the final duel in III was somewhat better as it was Anakin’s turning and Obi mourning his death, but even still, the poor script, acting, lack of chemistry, laughable dialogue….everything preceding it robbed that scene of any real impact. I felt nothing at a part in the saga that should’ve been the most heartbreaking.

The prequel battles were predicated upon poor film-making, and they needed to do something to compensate for that insufficiency: namely….flashy choreography. An amusement park ride void of any substance in the attempt to distract us from the real issue: that these are **** movies in all respects.

There is also much to be said for subtlety in the execution of dramatic release. The fights in the originals ebb and flow. In V, Luke eagerly turns on his saber at the start. Vader slowly does his, contemptuously, showing himself the veteran. Luke moves in, testing Vader's space. He makes a second strike with force, with Vader dismissively pushing him off with only one arm. In the prequels, when they are swinging 10,000 m.p.h in every direction, sabers clashing five times a second from start to finish without nary a breather, there is no room for dramatic flow to play on the audiences’ expectations or desires….to explore the nuances of the encounter and emotions that the characters have grown with throughout the films. It was all spectacle, and when everything's spectacle....nothing is.

I’d even go so far as to argue that the way they fought in the prequels was inconsistent with the mythos in general. Lightsabers are supposedly “elegant weapons of a more civilized age”. Lethality in grace. Yet they are spun around like some cheap glow stick baton that a high school cheerleader would twirl. Superfluous nonsense, no economy of movement, completely implausible for the fiction they reside in. These weapons are representations of their masters, professionals, and it detracts from their elegance and the belief that they are something not to be trifled with. Yes, the choreography in the OT is not the best at times, but you get the general gist that remained consistent with the lightsaber’s opening description in IV. What the prequels did to the sabers was akin to turning the elegance and beauty of a sniper’s shot into an assault rifle sprayed in fifty directions.

tl;dr: The prequel saber fights suck because 1) poor film-making could not support them, 2) they didn’t allow for any dramatic interplay as they were always a spectacle, and 3) they weren’t consistent about what we’d been told about the lightsabers up until that point.