Good points salmonid. Fads start with some usefullness, but then get blown out of proportion.
I fish a lot of glass rods, but is the issue getting a softer rod which could be of any material? Glass and bamboo have more weight so they can load with less weight of line out, but there are sweet soft graphite rods as well. Not all graphite rods are stiff tournament casting designs. One can get stiffer actions with glass. I think it is more about the action, which can be designed with different materials. What can't be designed in is the nostalgia factor which is high with my old Fenwicks, Phillipsons, and white glass Shakepeares. Love to fish rods from my past - even if they aren't as high performance as newer ones.
I've fished flies/nymphs with crappie poles for 25 years and especially like them for fishing in the winter when the guides and the reel get iced up with conventional gear. Got an 8' 6" Asian rod and it is fun for some cases as well. In general Tenkara rods should have a softer action than a crappie pole since a crappie pole is meant to lift a panfish into the boat or on a bank. Tenkara shouldn't be that stiff.
Two handed casting can be a blast and it is another skill that fits many situations better than single handed casting, not that you can't use a single handed rod. In general I would say get a real spey rod, but the shorter switch rods can be fun for some applications, like casting smallmouth streamers in rivers where you don't have room for a backcast.
A conventional fly rod is pretty versatile, but the "fad" rods fill certain niches. A 9' 5 or 6 wt can catch almost any fish in PA, but variety is the spice of life and some rods do better work for special jobs.
My only "old-man" complaint is don't expect a specialty rod to substitute for knowing how to cast well in the first place (which takes practice, practice, practice). No short cuts in life and equipment can't replace skills.
