It would seem to me that this is an excellent idea.
The Secretary of State, today at least, is America's principal representative abroad.
As such, they need to be able to speak for the President of the United States.
To do that, they need to have a great working relationship with the President.
It seems unlikely that the President and a Secretary of State would be as likely to have the necessary working relationship if both were having to respond to an electorate.
Additionally, one would want the Secretary of State to be a foreign policy expert and not a traditional politician.
