Not only. Yes, the emotions and build up help those fights immensely but the Mustafar duel has this as well and I felt that one was a dud. The other big difference is the level of brutality and violence in the OT/ST duels is lost in the elegance of PT's duels. In the OT/ST there is a sense of weight behind their lightsabers, they wield them like broadswords allowing them to smash and batter each other. You don't get this in the PT where they twirl their sabers like batons and because of this I think they are a hell lot less interesting.
I find Duel of the Fates to be be overly choreographed (but still enjoyable to watch) but Qui-Gon and Maul's first duel on Tatooine was done right. Faster and more graceful but the attacks were still brutal and looked like they intended to kill.
AotC's duels were all painfully choreographed and devoid of emotion. The RotS Dooku fight was noticeably choreographed as well but I liked it; it flowed well, depicted the difference in each character's style well and the last leg of the duel carried some real emotion.
Obi-Wan vs Grievous in RotS was rather underwhelming; a bunch of buzzing lights and no real substance. Palpatine vs Mace was a comedy. Palpatine vs Yoda and Obi-Wan vs Anakin were good, but the latter dragged too much and the former mostly wasn't saber dueling.
Must be preference. I don't see where a prop's physical weight increases or decreases the creative value of a choreographed fight.
The PT was definitely guilty of going overboard at times when it came to overproduced choreography. But I'd put quite a few TCW duels over any of the ones we saw in the movie.
OT duels are better "storytelling devices" but PT duels are closer to what fights between superhuman space wizards should be like.
https://www.youtube.com/watch?v=o9O3fapKrjI - this would fit perfectly in the OT.