I disagree. To do flat design well is as difficult as doing a skeuomorphic design. It's a different style, but one isn't easier than the other. A good flat design isn't actually totally flat. It has to have subtle shading that accentuates the design, the size and placement of elements is also important, etc. making simple look good is not simple! But perhaps many people don't realize this and that's why many flat designs don't look good / are difficult to use, because not enough care is put in making them.With flat design, no craftsmanship is needed because practically anyone can do it