I didn't think he was the reason the offense didn't do anything. The Patriots were extremely aggressive against the run on early downs because they knew for sure that's what was going to happen. On passing downs there was frequently nowhere to go with the ball. On most man coverage snaps Gonzalez had Garrett blanketed, and when they played zone they took good advantage of the situations to make windows consistently small.
Taking care of the ball might have made it the best showing against a Belichick defense he's shown so far. If developing him was your fallback plan going into the year, I don't think he's given you a reason to change it. Especially for a guy who also can't make decisions, but also can't throw, in Siemian.