I pretty much agree with everything said. The facts is Mark Sanchez has regressed. I do think it is negligent on the part of Rex not to have a decent backup for the team.
Now, we have a young QB who is in desperate need of some motivation and Rex has not provided himself with the tools to motivate Sanchez. I guess I wouldn't say it is criminal on the part of Rex, but it is definitely an area where he dropped the ball.
It's like what I claimed in the Rex vs. BB thread, it's the smaller things where Rex completely drops the ball and it is the reason why Belichick will always be a better HC.