Can't speak directly for Brody, but I prefer whm simply because it fits me, I've been full time healing in MMOs going back some 15 years. The whole mitigation healing thing is comparatively recent and I'm just not as comfortable or natural with shields as I am with good old fashioned big heals and HoTs.
The same reason sch don't have a better tool than succor/rouse/wd for dealing with T5 fireballs.