I think the problem is that heavy sink tips and\or heavily weighted flies used for steelheading - combined with often windy conditions - and the need to do a lot of mending, roll casting, and shooting your line - the slow action less powerful rods just aren't as practicle. The general idea is to do as little false casting as possible - and maximize the amount of time your fly is being presented to a fish. After you finish the swing, just strip in a little line, do a small roll cast to get teh line out in front, and then shoot the line on the next foward cast. Not as easy to do (with any distance) with a slower rod. Now for summer fishing for trout with dries on a calm day - I'd love to have a slower action rod... my .02cents.