I can't speak for other people, but I can perhaps share some insight from my feelings. Just to get it out of the way, it is a bit annoying to see a company that is normally absolutely obsessed with others copying them now doing the same. But as eyebrow raising as that is, its not really my main concern.
My personal issue with this design is that it signals the coming of a boring lull in mobile design. Its the death of distinction. Android, Windows, and iPhone now largely look the same (to me). In fact I think the Windows stuff actually looks better. Its upsetting because there are surely more than just two possible designs ("flat" or "skeuomorphic"). Did iOS need a design overhaul? I don't know (I'm personally of the belief that it was missing key features and services more than a new skin). But if for the sake of argument it did, then this just frankly feels lazy on Apple's part. It was the most obvious direction to go in, and its been done. Aqua and iOS 1 were different, fresh, and represented an original vision for UIs. Even if you didn't like them it provided something to contrast to. This just provides something to compare to :/