Yes, Penton and Jonsson are important.
Here's another non-American example that I recall reading about in the old KH library when I'd escape from the deadening meetings, duck inside, and read the old lit. There was a guy in the early days of the WTS history in Taiwan who was put in charge locally there (maybe under Rutherford?) but who had a falling out with the WTS HQ in NY, was removed as branch servant (or whatever they called it then), but took the vast majority of Witnesses there with him. Something like 90% of the active Witnesses there followed the guy for years. WTS growth in Taiwan suffered for decades. It was almost nil for that long. Once Gilead got going, they kept funneling missionaries in there but with no real effect. All this was written up in one of the old yearbooks from the 70s or thereabouts. I suppose that WTS growth has finally taken off there now, but the guy's effect was huge for a long time. In numbers it's probably more significant than the Bottings or Bill Cetnar.
Another name to ponder perhaps is musician Frank Kavelin, long-time big name elder in Los Angeles whose dad was tight with GB I. The son used to go to NY to conduct the WTS orchestra for assembly and other recordings. I don't know, however, of any big influence he's had in getting others to leave...
His story:
http://www.jehovahs-witness.com/topic/180011/dncall-unmasked-part-1-5?page=1
My two cents.
Glad to see you back and posting SBF! Bedazzle us with your intelligent contributions like you used to.