I thought the amount of thought that went into the Jedi Order for the prequels was astounding. Like the different levels of lightsaber fighting, the differences between the different Jedi's styles and what that says about them as people.

I think the prequel Jedi were portrayed differently because they were different. They had grown too sure of themselves, and lost track of their peaceful alternatives when they were re-purposed as generals for war. That's why Yoda makes his point about how "Wars not make one great" and Obi-Wan makes his point about alternatives to fighting. They had been down that road and knew what they were talking about.