I've read where a lot of NBA people believe this was this particular Jazz team's pinnacle and that there's not much room for improvement there. I have to agree.
Both Gobert and Hood will be 25 before next season, so I don't see any drastic improvement coming from either of them. Favors will improve a bit back to where he was prior to this year with injuries, but that's not going to move the needle very much at all. Hayward is in his prime and can't reasonably be expected to be better than this last year. They'll probably lose one or both of Hill or Ingles this summer, and they have both Favors and Exum coming up for major deals next summer that they're unlikely to be able to afford if they max Hayward and keep one of Ingles or Hill this summer, which is bad news considering Favors and Exum are the only two players on their roster that could significantly better their game in the coming years.
Honestly, outside of overall team defense, Utah being the "status quo," and them being able to offer the extra year, which I don't think will matter with Hayward anyways due to him probably opting out after 3, I think Boston has the advantage in every other area.