What Would Have Happened If Obi-Wan Had Confronted Palpatine Instead of Yoda
We know that Obi-Wan didn’t want to go to Mustafar to battle Anakin in Revenge of the Sith. He begged Master Yoda to let him go fight Darth Sidious, but we know the outcome of the decision. Yoda went to battle Darth Sidious in Senate chambers, and Obi-Wan went to confront his fallen padawan. What would have happened if Obi-Wan had gone to fight Emperor Palpatine? Would things have ended differently for Anakin and Obi-Wan? Was there ever any hope or point to the choices made by Yoda? I think there is a vast majority of fans who have asked themselves these questions. I certainly have pondered the possibility, and, while there is really no additional information to explain the “What if?” scenario to my knowledge, I think there is a conclusive answer to the question.
If there is a simple answer to the question, I think simply put, “He would die” would suffice. Obi-Wan just isn’t strong enough to face the Emperor, and we know this because Yoda told him that point-blank. However, that answer really doesn’t do enough justice to the gravity of the scenario. Obi-Wan wanted to go fight Sidious because he didn't want to have to face Anakin, a person he loved and viewed as a brother, and see the person he had become. He didn't want to kill Anakin, and he was probably unsure if he even could. It was absolutely necessary for Obi-Wan to face Anakin, though, and I think Yoda knew this.
By this point in Revenge of the Sith, the Sith had, well, gotten their revenge. The Jedi were all but defeated, and Yoda was finally coming to the realization of what led to this. He was seeing the folly and blindness the Jedi had prior to, and during, the Clone War. The Sith had won, and he feared that there was nothing they could do to stop the Emperor. He felt that he had failed, and as far as he could tell, the only hope they had was to defeat both the Emperor and Anakin in combat. If Obi-Wan went to fight Sidious, he would have been killed, and there would have been no hope.
To go further down this rabbit hole, Obi-Wan dying at the hands of Darth Sidious would have caused major problems for the future of the galaxy. Obviously, if Obi-Wan died, he wouldn't have met and trained Luke. If he couldn't train Luke, then Luke couldn't defeat the Empire, and the bad guys would win. Also, if Obi-Wan died and Yoda defeated Anakin, Yoda could have sent both children with Bail Organa, which could have easily led to both their deaths. You could make the argument that the Emperor, without an apprentice, would have been less of a threat, but it would still have come down to a fight between Sidious and Yoda. Although, I think there may be one other reason for Yoda’s decision.
I don’t think it came down to a pure decision of skill on Yoda’s part. If Obi-Wan had fought Sidious, he would have died. That has been well established, but I think Yoda was more concerned with the fact that Obi-Wan needed to face Anakin. Yoda wasn’t sure if he could even beat Sidious, but he knew he could keep Sidious distracted from their fight. I think Yoda may have suspected that Anakin was still the Chosen One even if he had fallen to the darkness. (Though by the time of the original trilogy, he would come to believe Leia to be the Chosen One.) That is why he sent Obi-Wan to Anakin. If Yoda had gone to confront Anakin, nothing would have changed. Obi-Wan would have been the only person that stood any chance of not only defeating Anakin, but also, most importantly, bringing him back to the Light. With Anakin on their side, they may have stood a chance at defeating Sidious and the Sith once and for all. It was a long shot, but Yoda must have believed it was worth trying.
In the end, we know what actually happened. If that was Yoda’s plan, it failed immensely, and this could have been why Yoda went into exile. He had failed to see the rising of the Sith, the folly of the Jedi, and how he had failed to save Anakin and defeat Darth Sidious. Yoda and Obi-Wan both went into exile, and the Empire was able to rise to power. Although, another hope would soon arise in the form of Luke and Leia. If Obi-Wan had faced Sidious, not only would he have died, but all hope would have also been lost in ever defeating the Sith and bringing balance to the Force. It was a tough decision, but Yoda and Obi-Wan did what they could with the hands they were dealt.