Rutherford turned Watchtower from a fringe belief to a serious business and used Fred Franz' strange writings, then Knorr fine-tuned the idea of "publishers" and was all about efficiency while he was using Fred Franz' strange writings. Fred Franz is virtually single-handedly responsible for keeping the "generation of 1914" alive for so long and including 1975 and "the 20th-Century." While there's nothing spectacular about Fred's presidency itself, it seems he was rewarded for his long years as the oracle with that title, and others saw the need to make a "Governing Body" and take away the all-encompassing power of the single leader. Also, Fred being there, further reward for his long years got Ray Franz onto the GB.
Ray is responsible for revealing more things about the GB than anyone else, responsible for more people waking up, and his situation is more of a reason why GB 1.0 turned further toward harshness and shunning.
Such a combination gets us to today's GB 2.0. So it's gotta be Fred who is most responsible for "process" now. And while his take on doctrines is pretty much dead now, GB 2.0 is having to deal with long-held Freddy writings in morphing WTS into something else. So Fred is still most responsible for doctrine.