I can understand the humor being off-putting for some but I don't think Thor's characterization was spoiled or anything in Ragnarok. Was he a little more jokey than before? Sure, we know that Hemsworth wanted it because he does have a natural comedic talent which he wanted to incorporate within the character. He does this in Infinity War (a little) and Endgame (a lot) as well. People have said that this doesn't fit Thor but I disagree. In Ragnarok, MCU Thor has spent enough time around humans like the Avengers that he'd naturally adopt some of their traits in his own interactions, such as the occasional humorous quip. But besides that, and more importantly, let's not forget that MCU Thor was never all that serious to begin with: