The quarterback needs to adjust his style of play to match the circumstances. I used to blame Arians for poor play calling but it was fine when Rothlisberger was out. We won games. The running game worked. But now its back to all about Ben. Stand in the pocket for an eternity with a patchwork offensive line. Constantly looking for a highlight reel play dowin the field instead of first downs. Brady gave a clinic on how to lead a young, inexperienced team to a win. Another example of why he is an elite quarterback and Rothlisberger is not. Watch the film Ben, even you might learn something.
Roethlisberger has had a lot of great games in his career. but he has turned in a surprising number of bad games. As the commenter noted, he seems to lack situational awareness. He goes for big plays when cold efficiency is the better choice. Against New England, the offense sputtered when the game was close. BR seemed unable or unwilling to take what the defense gave him and threw a slew of deep incompletions.
It was even worse against the Bengals. The Steelers had a double-digit lead in the fourth quarter. The only way Cinncinnati can make a comeback is if Pittsburgh gave them a turnover and a short-field. Roethlisberger promptly threw an unnecessary interception and the Bengals stormed back into the game. (In fairness, the head coach helped the Bengals out by trying for a long-field goal with a struggling kicker.)
I have to say that the Steelers were also out-coached. The team was missing quality starters on both sides of the ball. Yet, i saw very little creativity in the play selection or formations. The coaches just seemed content to use their basic game plan and hope that the substitutes could play as well as the starters they replaced.