I've thought about it before but I don't think it would have worked this time. The surface of the water has a zillion leaves and it's a bit hard to fish the bottom in 15 fow with a fly rod right? Also could you get a fish to chase a fly with mid 40 water temps? I'm sure it would be a blast in the summer tho!
You can catch fish on a fly all during the winter like you were catching, if you can get the fly to them. I fish a shallow pond during the winter from the bank, so I never know what the temp is, and I have caught them all winter, but not quite as well when the water is warmer. I use floating line, so I would not be able to get to those you caught, and all the leaves would create a big problem. Fly fishers who have been doing it much longer than I would have much better ideas. I would be like you, if it were that difficult. I'd be using spinning gear.