It was emotional to see Yoda pull out a lightsaber for the first time in AOTC and fight Dooku. It was emotional to watch Qui-Gon trying to hold off Darth Maul by himself while Obi-Wan was temporarily trapped. Those two duels, however, aren't as iconic as the duels in the OT or in ROTS. I think that's the difference. I would think that when most people think about lightsaber duels, a duel involving Luke Skywalker or Darth Vader would be the first thing that comes to mind.