If Luke already waited 6-12 months to go back to Yoda, what difference would it make if he went back one week or the next? And doesn’t it make just as much sense for him to have resolved the mission he set himself on before returning to Yoda? “I totally failed to save my friends, and still haven’t saved them, so I’m sure you’re really disappointed in me. Oh, you’re dead.”
Luke can pick up things with the Force without having been trained in ESB. He has the ability to progress without Yoda.
^ This.
I’ll also include what I’ve said before from another thread:
I think this does make perfect sense from a logical perspective [to have Luke training with Yoda from the end of ESB to ROTJ], but, the dialogue that is said during this scene keeps it from working nicely, for me anyway. Let me explain why: It would be extremely odd of Luke to be training with Yoda for even a short while and waits until Yoda’s death bed to finally ask that most compelling question - the question that has been echoing in his mind continuously ever since Vader’s revelation. There is no doubt in my mind Luke would ask Yoda this question ASAP. Sure, it’s kind of odd he doesn’t immediately go to Yoda for more training, but it’d be even more odd if he did go there and didn’t ask about Vader right away. So because of this situation, it just wouldn’t work moving this to the beginning of ROTJ - it needs to remain in its original place. I admit, even that deleted scene of Luke finishing his lightsaber is rather cool, but it needs to remain as just a deleted scene [and it sounds like it can’t be salvaged anyway due to its quality].
I said more, including how then he got knowledge for constructing his lightsaber and how the plan for rescuing Han could make better sense, so for anyone curious can click my name of that above quote to see the rest.