This is the policy likeliest to succeed, provided that you're willing to accept the secession of Western Iraq. Our government is opposed to that, but I see no reason why we should be at this point. Baghdad has proven it was, and remains, unwilling to treat the Sunni population justly. It held together while the US remained in Iraq to enforce the peace, and perhaps in time if we had stayed they would have learned to trust each other and work together. We left, and the Shi'a led government chose the path of fear.
It is that very dynamic that allowed Daesh, the so-called "Islamic State," to spread rapidly through Western Iraq. They are horrible people, though, and are preferable for Iraq's Sunnis only to the hostile and corrupt government in Baghdad. I would not be surprised to see a Sunni kingdom built around one of the larger tribal groups emerge from this conflict, a state perhaps like Jordan itself: not perfect but better than what they have now, and a buffer against Iranian efforts to dominate the Levant.