I think anyone who has dedicated themselves to the point that they make beer at home consistently of a commercial level is a homebrewing All Star of sorts.
But the REAL All Stars IMO are the people who took their knowledge and helped brewers on a big scale. People that act as ambassadors , even cheerleaders , for the hobby. The first for me and a lot of people (even though some of the info is a bit dated now) was/is Charlie P. His contributions to homebrewing, BA, GABF, etc. are gigantic. And another is you, Denny. We both know the spotty info that was around for awhile on AG brewing. You cut through the BS for a lot of brewers with Cheap n Easy AG, the same way Charlie did by encouraging people to try brewing in the first place. I would venture a guess that there'd be a lot more 'extract with steeping grains' brewers if not for somebody presenting AG as a cheap, easy alternative to better beer. Lastly, Martin has been huge in helping AG brewers dial in their pH - I never realized how much of a difference good pH made until I got it right consistently, on different styles, and not just the beers my water happened to be suited for.
There are lots of other All Stars out there, but those are the three that came to mind first.
EDIT - I've gotta add Major. He made the jump to pro brewer, is excelling there by all accounts, and makes time to be a mod here and pass on his wealth of info.