Re: your thoughts on synthetics
I think it's a matter of what you like to tie. I also feel there might be a generational aspect to it as well, but that will tie into what you like to tie.
If you look at many of the more popular waterwater patterns coming off of vices nowadays, they generally consist of more synthetic material than naturals with the exception of marabou. That is one material that seems to find it's way into a lot of patterns.
Streamers tend to use many more synthetics than wets, nymphs or dries. But that is where the generational thing comes into play, at least in my view. Many of the older fly fisherman, at least the ones I know, tend to stick with smaller, more traditional patterns. With those more traditional patterns, more traditional materials are used.
You'll notice that many of the younger generations find themselves throwing large streamers consisting of a lot of synthetics in both warm and coldwater applications. If you ever watch Brian Wise from Ozark Fly Fishing tie a fly on youtube, pay attention to the amount of synthetics he uses compared to naturals. It's probably an 80/20 split in favor of synthetics.
A few reasons I like synthetics over naturals are that they are more consistent. They also tend to come in more variations of colors, length, thickness, etc. Many, but not all, synthetics will also hold up better over numerous fish. I do find that with some materials you will give up motion in the water. When you're looking for a material that imparts more action in the water, generally you will want to stick with naturals. That's why marabou and bucktail will always be very popular tying materials.