(I don't like these quick put downs, they imply a finality that doesn't exist)

That The Gimp has been unsuccessful with a different interface to Photoshop does not mean a different interface could not be successful.

Imagine that an amazing new interface was developed that was so much better than what any product has now. Everyone asks why this has not been thought of before. Now imagine that it belongs to version 3.0 of The Gimp.

Just because one alternative interface didn't work, doesn't mean we should all give up and use the same interface. With that advice, nobody would ever try anything new.