Yeah, they probably could've done a better job easing him into it. At the same time, he likely got paid 7 figures to cameo, so I don't feel
too bad for the guy.
I actually think Hamill would have been fine with not being the main character of the ST. I get the impression that he just didn't agree what they did with his character and how his character was portrayed . In other words, he wanted the character to go in a different direction.
I mean, I don't think Hamill would've ever suggested "I should be the main character" in those terms. I think he knew the ST would inevitably be a passing of the torch. But at the same time, for him to suggest that the saber should've flown into his hand at the climactic moment of the film, which would've taken away the culmination of Rey's character arc, her big "moment"...yeah, I think he probably had some confused feelings going on about the whole thing.
But the funny thing to me is, the "moment" he got at the end of TLJ was so much grander and bigger than that anyway. And he got a big character arc out of it too. That he died doesn't matter at all to me. There was never a feeling of "we won't see Luke again". It was more of a "cool, now we'll get to see Force Ghost Luke in the next one" for me. Which is now confirmed.
I don't know, on a basic level I still have no problem with Luke's story in the ST. We establish Luke going into hiding and not wanting to be found because of his failure in TFA. In TLJ, we explore that further and delve into Luke's perspective on the failings of the Jedi Order as a whole, before eventually bringing him back around to being a symbol of hope for the galaxy and a believer...if not in the old Jedi ways, at least in Rey.
That...works, for me. It's a lot more interesting than him just being a straight redo of Obi-Wan in the OT, anyway.
The fact that Palpatine may have been pulling strings all along could add a tragic layer to his arc, where he blames himself for everything not realizing there was a darker force that he couldn't perceive driving the events in motion that would lead to the collapse of everything he loved. We'll see how that plays out, but I'm really interested.