I have wore the LL Bean wading boot brand quit a few years, which have what LL calls the Aqua Stealth sole and which Simms also offers on some of their brands. I have not had any trouble with this type of sole which I guess is some special type of rubber. Wear is good, no problems with wading, good for hiking, and they are exceptional on wet grass and muddy banks and the sole will not freeze in the cold winter air while walking.
I look for all the wading boots to go to some type of sole other than felt, to reduce the chance of carrying invasive organism from one area to another. You cannot depend on a large segment of people cleaning their boots in the recommended fashion.
I think Simms will put out a product which will be very dependable for safe wading for the individual and the environment