I suppose “uncommon” is in the eye of the beholder. I’m a mechanic, so I see broken/damaged airplanes every day of the week. What I’m saying is that an airplane with the greatest design purity isn’t always the one that is the most commercially successful. Look at the MU-2 and the early King Air. The MU-2 had greater design purity and more performance for less fuel, but the King Air beat it in the marketplace. Most airplanes that work commercially have design compromises that support operability. All I said was that I could see where a repairable leading edge might be such an advantage. Look at the Air Tractor products. They give up a bit of design purity in exchange for toughness.
Don’t get me wrong. I very much appreciate a design that can carry more than it weighs. That’s a real achievement. The Cessna 180/185 is remarkable in that way.