Are you a UI Researcher? If you are, your approach to gathering research by rebuking everyone else's opinions seems less than optimal. FWIW I prefer skeumorphic design. Flat design won because it made scaling everything easier. It doesn't need to be this way now that SVG support has become widespread
Of course your seven year old wouldn’t recognize icons on a ten year old OS. What are you, twelve?
Seriously, go put the iOS icons for Phone, FaceTime, Messages, and Numbers in your bottom dock in a random order, and see how easy it is to use.