The contention went both ways -- if you get the big "f/64" book it includes an article or two by Mortenson about how bad they were. Mortenson was very much a prisoner of his own notion that to be Art, photography needed to be Painterly -- that is, to ape the formal characteristics of the paint medium, not just the common ideas of compositional strategies or tone. He genuinely seemed afraid to let photography just be photography. So you see him doing things like the Metalchrome image on the PSA site, looking for all the world like a knockoff of Johannes Vermeer (because it is). This obsession with credibility by aping the past is painfully nouveau and a carryover of the worst sort of Academie mentality. Good grief, he paints-on brush strokes and makes little stone-chip markings with a razor on the prints. I'm sure he thought he was the modern Alma-Tadema mixed with Frans Hals right until the end. I think his front-light strategy mostly came from a desire to have redecing planes be darker while surfaces facing the viewer are lighter, rather like pencil-sketch shading.
All that said, I still think his ideas are useful ones to have in the available toolbox from time to time.