A noticeable change we've seen in early footage for Thor: Ragnarok is the tone the film takes with its story and characters. In particular, some attention has been given to Mark Ruffalo's Hulk and how he's be given more substantial dialogue than we've ever seen his green alter ego ever have. As it turns out, there's a very specific reason why that change ended up happening, and director Taika Waititi has the answers for why The Hulk is so erudite compared to his past incarnations. He revealed the motivation behind the change as the following:
Yeah, that was really, just like with Chris, just wanting make it more interesting for Mark to play that character, because in the films he just said one or two words and just destroyed everything, and that was the version of Hulk I think that everybody knows. But this version -- the smarter version -- it's just become so much more interesting and engaging, because he's been the Hulk for two years. He's a hero on this planet and he's had more time to just sit with himself and feel comfortable in his own skin.
With The Hulk on Planet Sakaar for an extended period of time between Avengers: Age of Ultron and Thor: Ragnarok, it's only natural that the character would slake his thirst for smashing in the name of his warrior's nature. It'd be a kind of physical and mental therapy for Bruce Banner's more gamma-enhanced half, which apparently has given him confidence and the ability to attempt to articulate better than he ever has before. So ultimately, the more self-assured The Hulk is, the better he carries himself, per what Taika Waititi told CBR. Which means that by time Avengers: Infinity War kicks off next year, we're assuming he'll be even more talkative as The Hulk.
That's not the only obvious change that Taika Waititi has set with the tone of Thor: Ragnarok, especially when compared to the previous entries in the Odinson's solo franchise. We've also learned Chris Hemsworth's Thor has received a bit of an overhaul with a haircut and a wittier nature. Rather than playing up the fish-out-of-water aspects, or even the high drama of the Asgardian politicking he was a part of in Thor and Thor: The Dark World, a more jocular action/comedy nature seems as if it will permeate this third chapter of Thor's life story.
So not only does The Hulk get to have more fun, but Thor gets to buddy up with him in a similar spirit as they have in previous Avengers films. Judging by the fantastic reception Thor: Ragnarok has been getting in both its overseas rollout and the critical response, it sounds like it's working like a charm. If there was ever a time to start trying to make a deal for those elusive Hulk solo sequels, now seems to be the time.