I think you are overestimating what a President can or cannot accomplish in his term. I believe the original intent of the founding fathers for the President was a rather modest role. Instead, we have created a myth that a President as a semi-god capable of moving mountains.
But since you are a rather idealistic person, may I suggest a new form of government. This one has no presidents. Instead, elected representatives learn to work as a group. Decision making is done with a culture of consultation, not based on partisanship or idealogy.