The US presence in these regions will foster more hatred and in the long run give more power to Taliban (and similar organizations) because of grass roots support.
The US leaving the Middle East would mean nothing to the Taliban, AQ, or any other group of thugs of that ilk. The US is a convenient lightning rod for those groups to use to recruit like-minded thugs, but if not the US, they would find something else.
The US has done some incredibly wrong and wrong-headed things in the ME. I don't know if our leaving would be good or bad in the long run, but it certainly won't make any difference to hate-filled terrorists.
Those who would sacrifice an essential liberty for a temporary security will lose both, and deserve neither. -- Benjamin Franklin