In my opinion the ONLY solution to the mess in the middle east is for the regional governments to step up and take care of things on their own. As long as the U.S. and allies continue to fight terrorism for the regional governments those governments don't need to expend as much energy or resources on issues that affect them directly. Saudi Arabia and Iran, for example, will never get along if they are not dealing with each other directly.
The problem is that the regional governments aren't equipped to handle the situations they are in without help from outside, things have escalated well past their tolerance points. No reaction can be strong enough for the hardliners or merciful enough for those seeking peace. There is no middle ground so long as its controlled by the United States and outside allies.
That means bloodshed, things would get worse quickly before it got better if the United States and other countries simply withdrew all influence. Do you think they should pull out anyway and let what happens next happen? Do you think they could stay out while the body count rises?