The powers of the President have strayed very far from the original Constitution but I believe that they would still be comfortable with their current state of power.
With President Nixon and the Watergate Scandal, I believe that he did have to give up the tapes although everything said in the oval office is supposed to be secret because of the severity of the scenario. He told CREEP to break into the Democratic Headquarters and spy on them which is completely unethical and probably illegal. He did not have the right to do this or keep the tapes.
Another example is when Eisenhower brought the Military in to help the Little Rock Nine. This was a good example of the Executive Power because if Eisenhower did not use this power then schools might have never been desegregated. This was a key moment in American history and is shown by how many books and movies have been made on the subject and how much importance is put on it during history classes and the Founding Fathers would have been proud.
Lastly, George W Bush used the executive powers when it came to the war in Afghanistan. He used his executive power to kidnap people, use warrant-less wire taps, and use questionable interrogation tactics. He did all this to "Keep America safe." This seems like it has gone a little far from what the Founding Fathers would've wanted, but it was all important in keeping our country safe and therefore is normally helpful and successful.
In short, the Executive Power is exactly where it needs to be right now, there is no need for an increase or decrease in Executive Power and it has no strayed too far from the original content of the Constitution.