In case you're not being serious: For them to build up momentum, the blade would need a mass. It has none, though.
Well, the original trilogy was, first of all, hampered by technical difficulties. In New Hope, a) one of the combatants is a senior citizen, and b) George Lucas had that dumb idea of Lightsabers being rotating silver... things. I don't know how to describe it. The saber had to have a cable connection for the motor in the handle to be operated. You can actually still see it in a few shots with Alec Guinnes. Also, if I recall what Dave Prose said, he could barely see in his Darth Vader get up, and it was difficult to keep balance.
In Empire, the fighting picks up drastically. It's still not as fast paced as the newer movies, but still, a lot closer to what we know of light saber duels these days. The fighters act more as if they are in a japanese sword fighting movie. Each stroke is carefully considered, a lot more probing the enemy. It's a different fighting style. They go even more action in Return, but even there, there are longer intermissions.
In the Prequels they go in balls deep. Running at each other, wildly hacking away. Count Dooku has a lot of the old fighting style, with many gracefull deliberate moves and a lot less meaningless hacking away. But the only time the characters pause in Phantom Menace or Revenge is when they are actually seperated, otherwise it's one long patched together choreography. You have one moment of suspense, with the famous Darth Maul shot, and then it's just non-stop action. With cutaways to Pandalilly and little Orphan Annie.