Actually, I think it would be a good idea for a president to remain in office as long as the people want him. If he turned out to be the best president ever, it would be a shame to force him out of office if he was actually doing an excellent job simply because of that rule alone. It would prematurely terminate his excellent work. Nobody could ever solve very many or our pressing problems in a single 4-year term these days - unless he was a benevolent dictator, which is an oxymoron.
:)