IMO the Jazz aren't going to trade for anyone until they get Memo back (and he's fully healthy and in the rotation) to see how he fits in with this team - and that likely won't happen until following the trade deadline. I think they'll be atleast a 50-win playoff team, but won't become an elite team until they add another ball-handler and perimeter shooter, and I don't think that acquisition will happen until next year.
This year the improvement has to come from within, Jefferson has to figure out how to flourish in the Jazz's system, Millsap has to become a reliable scorer, CJ has to get more consistent, and Hayward has to adjust to the speed and strength of the NBA. If all goes well, I think that can take Utah pretty far (well, maybe not the Hayward part), just not to that elite WCF/Finals level.