Totally agree with you. Tiller has not been better because he hasnt got enough reps to be better. He shows signs of improvement at times then he reverts back. Knowing that he truly has a chance be the guy may open him up to do things he never had a chance to do. Also, he was never pushed by Capello and he knew this was Austen's team. He didn't have a reason to be any better than he was. Only time will tell.
How has Tiller not had enough reps to get better? You lose all credibility, name any other back up quarterback that has played four full games, plus replacing AA in the baylor game a year ago, and scrap up time.