More TDs than INTs is huge to me (by a significant margin - say 8 or more). If he does this, that means he has started eliminating some of his mistakes and improved his red zone play. So, in my mind, this stat has to be solid.
Also, he has to improve the deep ball and hit the open receiver on those plays. I don't know how that is measured, but that has to improve. Many missed opportunities last year with Hartline.
I should note that I really believe that a lot of the poor performance in the red zone last year was horrible play calling by our friend Dan Henning and other factors that I can't place solely on Henne (although he certainly shared in the blame). The team could get the ball inside the twenty and just act like a completely different offense when they got there. Henning would get cute and run the wildcat or completely abandon whatever was working and go to something else. I remember numerous instances where there would be holding penalties and all kinds of other crap that sucked the life out of the drive. I think it is fair to say that the whole offense needs to improve here, not just Henne.