Uneven prefinished harwood
True, but there are a good share of square edge products that look downright ugly with the amount of "overwood" that's there. I call 'em sock catchers.
I have never had the sock catcher problem that you are concerned about. Most manufactures of prefinished flooring either micro bevel the edges so there are no square edges. There are companies that make square edge prefinished flooring that is is amazingly flat. You pay the bucks for the extra care they use in the milling tho. Robbins is one company that makes a good prefinished square edge hardwood floor.