I've said this repeatedly, but I'll do it again. NBA point guards typically experience the most explosive growth between the second and third year of their NBA career. It's likely that Jazz fans expect a quicker timeline because our last marquee point guard draftee, Deron Williams, had his major jump between year one and year two. It's important to note, however, that Deron's earlier jump is highly irregular when compared with the majority of NBA point guards. It is by far the most difficult position in the NBA to learn, due to the leadership requirements on offense and the mental precision that is needed.
Because Exum missed a year with the ACL, we can hope for this growth to occur going into next year, though it might be slightly delayed given the lack of continuity between his first year and his second (technically his third, since we aren't counting the ACL year.)
TLDR: next year we'll have a much better idea of who Exum is going to be as a player. My gut tells me he's about to make a gigantic leap.
