Yes, and if we this trilogy set ten years ago with Luke, Han, and Leia still as the protagonists, that's probably more along the kind of story we would tell. Or if we had a decades-long running comic book series featuring Luke's excellent adventures...you get the idea. However, Luke's story has been told. And portraying him in a way that preserves an idealized version of his hero-idol ascension -- making it a permanent one in the face of any minor, quickly-resolved stumbles -- would have been a far greater disservice to his character. Though it would have been satisfying, for sure.
TLJ and the new trilogy as a whole really makes a point of grappling with the question of legends. Behind the power of how they're received, who are they underneath?...e.g, Rose is star struck by Finn but then realizes he's cutting and running. And she surpasses her hero. Rey (and everyone) knows the legend of the great Luke Skywalker, but she surpasses him, too. Kylo is caught up chasing the image of Darth Vader, and it consumes him and causes him to strive for terrible things. The nice thing about Rey surpassing Luke, too, is it's not portrayed as a repudiation of him, it's a passing of the torch. Luke got it wrong with Ben, seriously wrong. But he got it right with Rey, and with one magnificent final assist he allows the 'spark to light the flame' to endure. That will go down as perhaps the most legendary thing Luke has ever done, and it's a beautiful culmination for him.
