I like a lot of aspects of the old school streamer patterns, not least the simplicity of many of them. Although many old flies like the Mickey Finn have fallen from favour with most anglers nowadays they still work. The problem I think, is that they don't look as natural in form as some more modern patterns and don't have the modern mobile materials that have replaced bucktail for many. The first one I think is a legitimate issue with these flies , stacked wings, clean cut tails and prominent black thread heads don't really add much imitation or suggestion of life for me. That's not to say that it really matters whether it suggests life to me if it suggest enough to the fish that they will eat the fly. The second point Is something that is becoming increasingly less important to me. When it comes to materials for bait imitations, I've already largely moved back to bucktail for a lot of my river patterns and almost all my saltwater flies. No it doesn't move and breathe like fox or marabou but then neither do actual fish. Bucktail moves wonderfully in the water and the fibres have a nice affinity for each other in which causes them to move much more cohesively than the softer materials. I'm gradually spreading this across my personal fly collection as it doesn't always make for the type of fly that others are keen to take off my hands.
I've decided to tie myself a box of old fashioned (is stuff from the 80s old fashioned?) flies to use for smallmouth bass next year and see if it has any impact on my catch rate. I'm sure these old style flies will catch fish in a lot of situations that modern patterns will but it'll be interesting to experiment. Even if you don't switch back to the old patterns it's probably worth adapting the colour schemes onto more modern profiles, which is how i'm easing myself off of the modern stuff. Give the old ones a try, or twist them up a bit different like I've done with the pictured Waterman's Silver Outcast.