Cost benefits analysis:
Fitz calls a good game and his ability to help the O line by quick decision-making and through adjustments at the line of scrimmage are important skills. His arm is holding him and us back, no question.
TJackson (and, apparently, my mother-in-law) has a better arm. But does that outweigh the other stuff? Will he put his O line in a position to succeed? Will he make the right audibles, or even just not cost us timeouts because he doesn't know the playbook? Will his unfamiliarity with receivers and their routes mean that the benefit of his better arm is not going to be realized? (SJ seems to run somewhat unorthodox routes, at least getting off the line, so don't assume that he will easily mesh with a new QB.)
Chan is weighing these questions now, and it isn't clear to me what the answer is. It couldn't be any worse Fitz right now? Yes, as bad as he is playing (no excuses, it's bad), I could see how it well could be worse.
kj