So right about the “sophisticated” part. I actually think it’s the opposite that it takes a better designer to complete a flat design UI, not to many can pull that off. Google are doing a good job in the iOS apps.
If Apple is gone go with a more “flat design” I hope they go more in the lines of Google’s iOS apps, they have stepped it up a notch. To be perfectly honest I think Microsofts Live Tiles are good looking on the phone but especially on a tablet or desktop it’s really beautiful. But the rest of the OS is poorly designed. To each is own, it’s not for me.