Nope, that wouldn't fit in with the sense of fading, both for good and evil. The First Age had great monsters and legendary heros, while the Third Age had only a few dragons by then, and much less mightier heros(Not that Sauron was less effective than Morgoth). The next Dark Lord will be less than Sauron, but nothing says he won't scheme better against the more dominant and more foolish humans.