Why do people always get divisive? Most of the classical I played WAS folk--old lute dances and such. I was asked to play a theorba for a concert, and had never played one, the classical guy said don't worry, it plays just like a strat.

   Barres and other chords are mostly holding a shape with your hands, and trying to use as little pressure as you can. So if you're used to a narrow neck, a wider one sorta feels harder. It's good to learn muted barres too, selected notes with the others merely stopped. It's not really much easier without the pressure, you still have to learn to hold the shapes.
I'd tend to agree, full barres are often mushy sounding, too many notes, just because they are there. I don't think I could do any barres without my thumb behind the neck, but I'll let it creep over on 1rst position things, sometimes mute or hold a bass note there. Why I'd ever need it for the fourth string is beyond me.