Luke was right for wanting to kill Kylo. He was a Dark Side user who would destroy everything. He's a little brat that killed Han Solo.
Everything he saw in his vision was correct.
The Skywalkers are a murdering death cult that are a huge plague on the galaxy. Luke and Leia are the only two that aren't giant assholes.
The Jedi don't need to end, but the Skywalkers do.
I didn't buy that Luke would stay on the island, but that's not really Rian Johnson's fault, JJ Abrams set it up that way.