Alright, first things first: I know it’s still in beta. I know that it will improve before public launch. But still, this is Apple we’re talking about. They’re better than this. iOS 7 sucks right now.
The native apps are being advertised as “simple.” I’d call them simplistic. I love minimalist design, but I believe interfaces need clear boundaries and visual cues. Plain black text on a plain white screen might be beautiful—and it often is—but it might not be very usable.
Borders and their UI companions define interact-able objects and regions. Plain text and whitespace do not.
General impressions & comparisons
The UI looks similar to Google properties like the GMail and Google+ apps. But that’s bad for two reasons: Google is your biggest competitor so stop emulating them; and it’s not iPhone. It’s not the identity you’ve built. It’s not what your users know and love. It’s not Apple.
Apple essentially invented the mobile device UI and its guidelines. They’re the reason buttons have texture and dimension. Now they’re abandoning that in the name of “simplicity.” In my humble opinion (and it really is humble), I think Jony Ive should hand over the UI reins back to whomever held them for iOS 6. His hardware design is gorgeous and iconic. His UI design is not.