I think Obi-Wan's fighting in ANH is weak sauce because it's likely he hasn't used his lightsaber in almost 20 years.

Nevermind the fact that Alderaan just blew up and that great disturbance in the Force probably did a good deal of damage on ObiWan's Force-chi or whatever.

Dooku, on the other hand, is a Sith. He gets his power from hate and anger. In ROTJ, Luke didn't start kicking Vader's ass until he got angry.

I have no problem with the Jedi & Sith in the prequels being able to jump around and stuff, so long as the fight makes sense. Sadly, though it looks nice, a lot of the time it was just flash without substance. In each of the duels in the OT the combatants are carrying on a conversation as they fight. But in TPM, for example, after the Jedi Council tell Qui-Gon and Obi-Wan to discover who this new Sith guy is, when they encounter Darth Maul they don't ask him a single question. Wasn't it their job to find out why he was there to kill Amidala, who his master is maybe, how did this Sith come back... you know?

It really wasn't until EpIII that we started getting some dialog during duels again.