Hello from SW Florida!
Downsizing is great: less to clean, easier to store, more places to camp, easier set-up and hook-up, and a smaller, more fuel-efficient tow vehicle.
It also involves some compromises: wet baths, crawl-over beds, no lounge seating, smaller holding tanks.
Molded fiberglass has distinct advantages over conventional framed construction, the biggest being fewer seams to leak and high resale value.
Best advice is to get a look at some options first-hand. Rallies are one way to do that. You can also work with manufacturers, many of which have a referral program to connect prospective buyers with current owners willing to demo their trailers.