In a real sense Russell has been demoted and Rutherford has been promoted by the recent “faithful slave” change which, as far as I understand it, teaches that the faithful slave only came into existence in 1919. This means that Russell was never part of the faithful slave and that Rutherford was the leader when the faithful slave was selected.
I think Fred Franz is up there with Russell and Rutherford as one of the most important leaders in Watchtower history. He dominated the written religious output of the organisation between 1928 and the 1980s, including most prominently their Bible translation.