I live in Illinois but do all of my trout, steelhead, and salmon fishing in Michigan for the last 20 years. Michigan has fly fishing only on several rivers (Big Manistee, Little Manistee, Ausable, Pere Marquette) a no kill section and FF only on the Pere Marquette and also the Ausable system. About a 100 miles of river are designated special regulations such as above legislation is in process to possibly expand it up to 250 miles I think. Has been very successful to date, however it is controversial with the non fly fishing anglers for sure, since prime blue ribbon waters are those which are designated for special regulations.
I was 17 years old when the Beaverkill in NYS had its articial only no kill stretch established in 1966. Fishing remains good 36 years later. All of the michigan rivers which have had this implemented also have resulted in improved fishing.
More is needed IMHO.