I'm beginning to have my doubts about Sheridan, but the real issue is I don't know how you really assess how he's doing as a coordinator.
Right now, in my opinion our problems break down into these percentages:
5% dropped passes
5% play calling (but what would the play calling look like with an effective offensive line?)
I think Hiller is likely done after this season. Allen has showed he will make changes if they are needed, and I think this has become obvious as a change that needs to be made. The biggest problem we have is that our playbook is extremely limited because we can't block ANYTHING that takes longer than 2-3 seconds to develop or the qb gets sacked, and we can't reliably open any holes on running plays.
A lot of people are criticizing Sheridan as a play caller, but I think he deserves more criticism with how the qb's are performing.
I think Penix came back too early and was battling to get mentally into the game, but with two qb's having the same interception problems, it's becoming somewhat of a trend this year. And to be clear, the interceptions yesterday weren't good defensive play or batted ball interceptions, they were full-on "what are you doing?" ball-thrown-right-to-the-defender type throws.