Barnett is not that much better of an option. My problem is that everyone on here defending SJ keep saying that he is still learning and that he will get better. When? He is a senior and we are counting on him THIS year. There is no time for him to take his lumps and learn as he goes. If we are willing to accept a QB that is still learning then why not go with one of the young guys? Steele is gone after this year period! No time for learning on the job
My guess is that this assessment will be made after 2-3 conference games.
If SJ is cruising along, he will continue to be the starter.
However, if his completion % has fallen back down into the mid/lower 50% range, and if he is consistently making bad turnovers, he'll be replaced, because as you suggest, there is no reason to stick with a senior that isn't getting it done, when there are younger QBs who can achieve the same results.
However, it is way too early to make this judgment.