In the wake of Force Awakens, we’re still arguing that a Jedi needs extensive training? 😉
No, just that Luke acts like a very different person in a way that is hard to reconcile with the film’s only implied explanation (that he learned his lesson and nothing else). And Yoda just sounds contradictory.
This crawl is well-written, but it begs the question of him leaving then going back and being surprised that Yoda is dying if he had JUST seen him a week before.
It’s not a perfect solution, but it is a lot easier to believe than the alternative (for me at least). Besides, if Yoda’s 900 years old, who’s to say he shouldn’t have shown signs of dying back in ESB?