Fernley is better classified as a city in my opinion. It's one of the principal cities of the Reno-Sparks-Fernley CSA (which should be taken with a grain of salt as it's loosely defined), and is significantly larger than nearby places classified as towns such as Dayton and Fallon. I also think putting it up against Reno and Carson City is unfair considering they render at a different level which indicates their population/status as a capital over the less significant cities which render at zoom level 7 such as Winnemucca, Elko, and Ely.

I also want to talk about a couple other places, like Sun Valley and Spanish Springs. By US standards, they would informally be "suburbs", but the tag place=suburb uses a Euro-centric name is explained best by the OSM wiki as a "a major area in a place=town or place=city with a distinct and recognized local name and identity". Places perfectly fitting this definition are the five boroughs of New York City or more loosely-defined named areas like Stead in Reno or Centennial Hills in Las Vegas. Sun Valley and Spanish Springs are census-designated places fully-located outside of any incorporated community.

A lot of the villages you downgraded to hamlets are better tagged as villages to better reflect their populations. Places with such a population as Wadsworth (which is 991) are often tagged as villages and sometimes even towns in the US. Place=hamlet like basically all place=* tags is very Euro-centric and will inevitably need to be used differently to varying degrees depending on the country. It's better to make judgement on how a place should be classified based on its local surroundings rather than to refer to the OSM Wiki which typically uses descriptions that are universally broad or specific to Europe unless stated that it applies to the US or a specific US state.