Violin makers have known for centuries that one the most important things is the finish.
There's still a market for $30K+ violins, actually a waiting list. You don't find that in guitars, and because of that most guitars are finished with modern finishes. The expensive violins are still finished the old way.
This site had a big effect on me:
http://www.mother-of-tone.com/lacquer.htm
I've made a few cabinets along the lines of what he says there, with homemade varnish and I'm convinced he's on to something, which isn't really something new but something very old.
The way most guitars are finished came from the advances the DuPont Company made in car paints for Henry Ford 100 years ago, and it's based on making things quickly and great looking, not for aural reasons.