We finally get some sense of integration of the previously messy messaging apps in Android with Hangouts. But now we have Photos and Gallery. And Photos keeps going back and forth to G+ app. WTF? The regular Gallery app can already view the pictures from the cloud/G+. It's just like the messy messaging stuff all over again.
The grey icons on the notification center. In the past, it's grey when there's no connection to Google's server to sync accounts, and blue when everything is fine. It's a great quick diagnostic tool to see if you actually have data connectivity even if you are connected to a cell tower, especially when diagnosing cellular connectivity. Now, you don't know. Also, the indicator when there is data moving in-out is moved to the pull-down control center instead of directly on the notification icon. -1 for easy diagnostic tool.
Camera icon on the lock screen. I know it's there to indicate that one can start the camera app straight from the lock screen (instead of just a vague hint of something on the right side in 4.3). But then there's the Google Now arrow in the middle, giving a false hint to swipe up to start the camera (like the iPhone) instead of swiping from right to left.
The oversized icons create oversized opened folders that make the screen space feel cramped. Same thing on the app drawer, showing less apps per page.
The same stock camera app with its ADHD yet slow focusing.
What are your annoyances so far?