In the most recent newsletter, Disney Rewards Insider, Mark Hamill was interviewed and shared some of his thoughts on Luke's direction in The Last Jedi, which has been the subject of possibly the most speculation of any aspect of the film:
Hamill was asked if Luke turns to the dark side, as the trailers indicate might be possible:
In Star Wars: The Force Awakens, Luke has lost confidence in his ability to make good choices. It haunts him to the core. But he hasn’t gone to the dark side. This isn’t an evil version of him. But it’s still an incarnation of the character I never expected. It has pulled me out of my comfort zone. It’s a real challenge.
Asked about his reaction to the line, "It's time for the Jedi to end," Hamill responded:
I’m sure this line is a great shock to the audience, so you can imagine how I felt! This is a huge change for a character who once represented optimism and hope. It’s a radical decision to drop out of everything he’s ever believed in. The entire movie is filled with these kinds of jaw-dropping surprises, but you’ll just have to see the film itself to discover what they are.
Most of us think the trailers are full of misdirection and trickery. We also know that Hamill is the king of good-natured trolling of fans on social media. We obviously take everything with a grain of salt, but something about this interview makes me feel there is some sincerity and honesty from Hamill.