Not if the question is, "should your PG be able to shoot a decent percentage the entire game?"
If the question is, "does Trey occasionally come up big in the 4th quarter of games in which he hasn't shot the Jazz OUT of contention by hitting just 30% for the first three quarters?," then the answer is Yes.
In all seriousness, we won't know until next year. It is true rookie PG's struggle, perhaps moreso than any other position. Let's give him another year before deciding he has to be replaced. Of course if the Jazz draft Exum or Smart and we have a Green/Stockton situation, then Trey becomes "Treydable."