Although the answer to this question will vary depending on your personal opinion, I would argue that this is not the case. I do not think that the use and abuse of the informal powers have created an imperial presidency.
The informal powers of the President are not especifically written out in the Constitution. Nevertheless, they are required to be used under certain specific circumstances. These are not meant to be used regularly, and they include the ability to enact a legislative agenda, executive orders, sending troops without a declaration of war and conducting certain foreign policy initiatives.
These informal powers, even in the present, are used only on very specific circumstances. Most of the time, the president only employs the powers that are given to him especifically by the Constitution. Therefore, informal powers still represent only a small part of the role of the president and of national legislation.
