I think entomology would interest me most. I flyfished almost exclusively for about 15 years, but put the rod down when I moved away from the good rivers I was familiar with. Not knowing lake fishing (and the tendency to drag "wet" flies like chironomids and such) I just ended up switching to lure fishing. I haven't been back since.
So, just like I have found some very good reading here about what to fish with, at what depths and locations, at which times of year for different types of fish, I would find it really helpful to know more about hatches, identifying bugs, and fishing surface vs. subsurface. I think if I could get away from my comfort zone (black ant, stimulator/hopper, prince nymph and elk hair caddis) and flyfish with more confidence on lakes I might actually start flyfishing again.
Great question, Marc, and great feedback everyone. Looking forward to your articles!
JOHNNY K.Liberty Lake, WA