Agreed. Trevor definitely needs to improve as well to be thought of as a solid QB.  The long game appears to be the most obvious shortcoming, although some of that might have been from the bad OL (and bad running game) just not giving him time to set and throw long much last year.  

We know he doesn't have a rocket arm, of course, but physically I think it's good enough to get the ball there.  Then it's more a matter of timing and accuracy -- things that should improve with more reps and game starts.  

And as usual, whether we have a better OL and running game.  That's still yet to be seen, although there is some reason to be more optimistic about both this year.