I've always thought of the Canonflex as a false-start rather than a serious professional camera. It wasn't part of a "system" as the Nikon F1 was. It never got any traction although it was Canon's first SLR. There were later Canon SLRs (Pellix, for one)... which is where the FL mount comes from. At the time Canonflex was introduced, most professionals weren't using 35mm anyway and thought of the 35mm rangefinder as kind of old-fashioned. They were still mostly in the speed-graphic world or the 6x6 world. As far as I've read, it was the F1 that finally convinced the majority of professionals to consider 35mm. When they decided to get serious about professional 35mm cameras, they produced the F-1.
It seems to me that Nikon defined what a professional camera system (lenses, finders, bodies, motor drives...) should be with the F1 while Canon ignored the pro 35mm market for almost a decade. When they finally took the plunge, they brought out a camera that I believe is the equal of the F2. Their second (third if you count the F-1n... a minor upgrade of F-1) effort at a pro camera was the New F-1... which is the camera that I have now.