(I already gave up changes to the fisher-price UI).
Exactly what people called the current UI style (Aqua) when it was announced. Clearly Apple was right about that decision back in 2001, and I have a feeling they'll be right again. People never change, always hostile to the unfamiliar, few people greet unfamiliarity with an open mind.
I've used iOS 7 on a daily iPhone for over a month now, and I fail to see how the UI is any less mature than the current one. Aqua was (for its time) also very colorful and playful. If anything, I feel it is more refined and beautiful, they picked colors that can be fully appreciated with todays retina displays. Beauty is in the eye of the beholder I assume, I just find it funny that half the people bitching about it will more than likely grow to love it and completely forget they ever disliked it. But just remember that History never lies. Aqua was just as divisive as iOS 7, people found the gloss and shadows distracting, they thought that very high resolution and highly detailed icon artwork was extremely distracting and took away from the purpose of an icon, among many other complaints. Now these same people are complaining about iOS 7 GOING AWAY from these same things.