I gave this some thought, and the answer is lots - but you need to be here over the long haul to realize that. This is just the dead guys. It's a much more inclusive list for the living guys - even all the major Canadian architects have been discussed a few times each.
Ones that come to mind: Mackenzie, Colt, Tillinghast, Thomas, MacDonald, Raynor, even Banks, Maxwell ,Thompson, Ross, William Flynn, Charles Alison, Willie Park Jr., Tom Simpson, William Langford, Walter Travis, even Hugh Wilson, Old Tom Morris, Deverault Emmett, Tom Bendelow, Billy Bell, Eddie Hackett, Eddie hackett
Ones that I don’t think we have: Max Behr, Herbert Strong, James Braid, Herbert Fowler, Herbert Leeds, J.F. Abercromby, John Low, George Combe, C.K. Hotchkins, Horace Hutcheson, Chandler Egan, Robert Hunter, Walter Hatch, James MCGovern , Kinja Fujita, Wayne Stiles ,Vernon Macan, Mackenzie Ross, Alex Russell ,Fred Hawtree ,Red Lawrence ,William Gordon
Eddie hackett
I think what this thread is reacting to is Tom Doak is discussed more than anyone else since he chooses to actively participate in the site. Why wouldn't you discuss his work when he's here to answer your questions. Others like Brauer, recently Jim Engn, Lester, Kelly Blake Moran etc. have also been discussed with them piping in too.
The fun for me is when someone has the capacity to discuss a new architect and some of those threads have been jewels for someone like myself. That said, its tougher to do that with a living architect because of people's sensitivities which was well illustrated through Pat Ruddy's retorts to a thread. The architects have egos and feelings - and I think some would perfer not to hurt feelings or bruise egos and avoid the discussions of their work.
I know from my perspective that its hard to tell you how bad Brauer - er how good Brauer is for example.