iOS7 looks like the product of novice graphic designers that I have worked with at a development agency.
A couple of points why:
1. Colors - They use incredibly saturated colors. Let me tell you why they did this. In the print world, designers would often use the most saturated colors because this would give the most color and would make them more visible. However, what comes out of a printer is different than what is shown on a monitor.
Take a look at the diagram below. The amount of colors in print (CMYK) is a smaller spectrum than digital (RGB).
What does this mean? I believe when Jony Ive became the Chief UI Designer, he used a print / industrial design approach to iOS. That's why everything is so saturated. Take a look at the differences between iOS6 and 7 below.
These intense colors are way out of place and are unnecessary. He could have dialed back the saturation a few notches, and it still would have been enough to distinguish elements in terms of visual hierarchy.
2. Padding - This one doesn't make any sense at all to me. Fine, they screwed up the colors. But let's make everything close to the edge of the screen? What???
If you notice, a lot of the buttons on the top and bottom bars have very little space between the edge of the screen. Visually, to make things easier for the user, you need to provide a good amount of padding. Our eyes can't distinguish between the buttons, the title, and other elements. Everything's jumbled together.
3. No Drop Shadows - If you notice, the title of apps are almost next to impossible to read now because they got rid of drop shadows.
How am I supposed to read this?
4. Relative Design - The design changes to the color of the background. Sounds cool in theory but ultimately too many variables to cover. They got rid of the bars on the lock screen, fine. But then they went against that principle and added a color bar to the home screen that changes based on the color of the background. Sometimes it looks okay. Sometimes it looks absolutely dreadful. Why do we need to limited to certain backgrounds to make sure the rest of our operating system look okay?
5. Frosted Glass - There is a reason why designers moved away from stuff like this. Because it is tacky. What benefit does this bring to the user experience? Fine, you can somewhat see what's in the background, but it's so blurry that it ends up being completely pointless. And again the whole relative design. If the background is white, then I can't see the program that is in front of me!
6. Icons - Everyone knows these are ugly. It looks like different art directors worked on each one, which I believe is the case since Jony Ive said the marketing team worked on these. The freaking marketing team. Enough said.
Jony, you say you love minimalism. Yet your settings button is nothing but. Let's add as many spikes to the settings icon as possible.
There's a lot of stuff I could on and on about, but I wanted to vent these points.