Well, if Yoda & Obi-Wan are talking about which one of them should go kill the Emperor, it would be logical to conclude that one of them intends on doing this. Again, my big issue with Yoda in the prequels is that, too many times, he's made to look incompetent and lazy. He senses all these bad, ominious feelings from Anakin from day one, and clearly admits it in practically every film. Yet, Lucas has Yoda either reacting to it (Sandpeople massacre), or Anakin coming to him with troubling visions without doing a thing to counteract this downward spiral. His advice to Anakin in ROTS is the equilivent of saying, "Don't dwell on the imminent danger. Just let it happen, and don't worry about it." Clearly, Anakin's having much deeper troubles than for those lightly chosen words to aid him at all.
Also, having him fly around with a lightsaber, IMHO, turns him into a cheap action hero devoid of true wisdom or substantial power. In ESB, Yoda is talking all about the power of The Force, and that, because it his ally, his is powerful beyond physical strength. Also, how is it that Yoda is able to levitate the X-Wing Fighter in EMPIRE with the same ease as us carrying a blanket, but in AOTC, he appears to be straining himself to levitate that piece of equipment that Dooku drops on Anakin & Obi-Wan? Yeah, maybe he's worn out because of the saber fight, but that only goes to show that Yoda's power is very limited. He can only call on it in very short bursts, and is exhausted by it. Plus, by the fact that Yoda loses both duels he's involved in, it diminishes the perception of his power. He can't beat Dooku, he can't be Sidious. He's no more capable than any other Jedi.
After showing us how weak, shallow minded, and incompetent he is in the prequels, how is one to be convinced he's the right person to train Luke in the OT? I also don't like his B-movie action hero posturing when he confronts Dooku or Sidious. Yoda is not an action hero. In the OT, he was the source of wisdom and mysticism in Star Wars. He made you believe in The Force, and the power it could give Luke to overcome evil. Also, little is ever resolved in a lightsaber duel. It's more of a plot device to twist the storyline into a new direction (which is not at all a negative thing). Yoda's lightsaber battles really do nothing for the plot.
For instance....in TPM, the death of Qui-Gon gives way to Anakin being less-than-well trained by Obi-Wan. The death of Darth Maul opens the way for Dooku to become the new Sith apprentice, and setup the circumstances for the Clone War. In AOTC, Anakin charges into battle, gets his arm chopped off, and begins to lose more of his humanity from this loss. It motivates him to kill Dooku in ROTS, and his death makes way for the rise of Darth Vader. Obi-Wan destroys Grievous, and thus, motivates the end of the Clone War, the attempted arrest of Palpatine, and Anakin's turn. Vader vs. Obi-Wan results in the half-man, half-machine Sith Lord, destroying Anakin Skywalker further. Ben's death in ANH allows him to become "more powerful than you possibly imagine" by becoming one with The Force, and helping to guide Luke anywhere at anytime. The EMPIRE duel clearly sets up a whole host of character and plot twists to the point where in ROTJ, the duel becomes the catalyst for Luke to put down his arms, and ultimately, instigate the event that turns Darth Vader back into Anakin Skywalker. What do Yoda's saber fights do to further the saga along? Nothing, as far as I can see.
-NJM