Yoda should NEVER be seen with a lightsaber. Ever.
Even if I like watching the Sidious/Yoda fight, I understand your thought about that.
In my Silent Star Wars fan-edit I choose to let the end of the order 66 as the only moment we see Yoda with a lightsaber, because it's quick, elegant, Yoda don't wast time and energy jumping everywhere and he goes straight to the point. Even an old Jedi could do such a thing: focusing all his energy into a quick fighting move.
The only problem I have with all his fights in the PT is that in ROTJ Yoda dies at 900 because he's old and weak, so in ROTS he's something like 880... How could he turn from a fighting Jedi full of energy to a dying old creature in "only" 20 of his years? A bit strange.