More and more builders have eliminated plywood seat backings, replacing it with various types of plastic, sometimes even starboard. We may yet see the end of rotted seating in the majority of boats.

We are finding more boats with fully glassed deck to hull joints. Mostly in the mid size range. You'll probably never get this on smaller boats, though.

Less cheap, plastic hardware.

Better windshield design and finishing. Big strides have been made in reducing windshield corrosion by most builders, though there are still some bad ones. We don't see nearly as many weak, flimsy windshields.

Better headliners, We don't see as many glued on fabric headliners falling down, or bleed-through stains from glue. Velcro attached panels have revolutionized the quality headliner installation by making them easier to fabricate and install.

Mid level quality builders and builders of mid size boats: We generally see better engine room layouts with greater emphasis on ease of servicing. Sea Ray has definitely done better.

Fewer leaking windows, partly because fewer boats have any windows at all. But the idea of putting in long, skinny windows in express cruisers that weaken the decks has largely been dropped. The use of smaller windows, and giving decks better support has helped.

In the last 10 years, the number of lay up voids or voids in gel coat has declined dramatically. Much of this results from the awareness that voids cause blisters, and improving lay up process through better training of lay up crews.

Blisters. I'd say the verdict is still out, but I seem to detect a trend in fewer instances in bottom blistering. Unfortunately, builders may have achieved this by reducing quality in other areas. blister-resistant isopthalic resins cost double that of standard ortho general purpose resins, so that the cost has to be made up somewhere.