I kind of like broody hens. No knobs or dials, extension cords, etc. But it is an instinct thing, most breeds have had instincts bred completely out of them. I can see where one would think that broodiness was a disadvantage, if they had only dealt with birds that went broody without the proper instincts to be a GOOD broody. Don't get me wrong, egg production is not to be found in broody type breeds. But the beauty of chickens, with the advent of wire and using our opposable thumbs, we are not doomed to choose only one breed.
Most visible traits that have been selected for are purely for fancy, and are detrimental to the birds overall survival, but with our help, they do fine. Other traits are evolutionary outcrops left over from when chickens were dinosaurs. Like the rhino horn that pops up on Shamo from time to time.