They redesigned the entire OS in like 6 months. It's Ive's first major foray in to software design. I think we can cut Apple a little slack here. iOS 7 might not be perfect but it will get refined and improved upon. I suppose Apple could have waited until iOS 8 for the full redesign but then people would have complained about the UI being stale, Apple is doomed etc. I'm not judging iOS 7 until its installed on my phone and I get the opportunity to actually use it.
You're right, it will get refined and I hope it becomes a lot more polished before the final version comes out to everyone.
While details may change, I personally feel that the general design language is confusing and harder to use. I've been running iOS 7 on my iPhone 5 since WWDC and I've noticed a few things:
There are a lot of menus that just disappear. So, in order to do a function, the user needs to do an extra tap just to bring the buttons to view.
For example, changing pages in iOS 6 Safari involved:
1. Tapping the "page change" icon.
2. Changing pages.
Now it involves:
1. Quickly scrolling down or tapping the URL bar to reveal the bottom bar of Safari, and the "page change" icon.
2. Tapping the icon.
3. Changing pages.
Now, this sounds like a small annoyance but I think it's revealing of the general missteps that have been made in the new UX.
Also, the constant white, similar icons, and thinness of text (and at times icon glyphs) can feel overwhelming at times, and makes finding the button you need more difficult.
General readability also suffers. Safari provides another great example of this. Now, tapping 'reader' often makes the article harder to read, due to the thin text and bright white background.
There are some good features in iOS 7. No, Apple is not 'doomed', and I'm sure iOS 7 will improve and iOS 8 will be better still. But the problems with iOS 7 do, I believe, go beyond 'childish icons'. There are elements of the new design language that I believe are simply not the right way to go.