[fallwithme]

> The most important "action" on that screen happens when you press a gray text on a gray background!

The "Send" text is gray because the input box is empty. When you typed in something, it will turn blue. Still not as intuitive as a button though.

> Also how can I reject a call?

It's exactly the same as in iOS 6. There've always been two different call screens since the first release of iOS. One is shown when your phone is locked, where you need to slide to answer and push the power button twice to reject. Another one is shown when your phone is not locked, where you have an answer button and a reject button. The screenshot causes the confusion because it is comparing the second call screen on iOS 6 with the first call screen on iOS 7.

[Vieira]

You are completely right on both. I'm sorry, my mistake. Regarding the Send button, or lack of thereof, it is much better blue than gray but, as you said, it is not as intuitive as a button. There is a lack of perceived affordance. It's one of the top 10 mistakes in application design that Nielsen[1] points. Of course Nielsen can be wrong and Apple can be right.

[1] http://www.nngroup.com/articles/top-10-application-design-mi...

[robmcm]

Discoverability has taken a hit, try finding spotlight search, you have to scroll the home screen icons down. Something that makes no sense, and if you scroll from the top of the screen you get the notification centre.