They chose grey because the icons will be slightly semi-transparent in the final build and will take on color from your background. In that sense, it's a pretty brilliant design.
The change to the camera icon makes a lot of sense if you've ever watched a first-time phone user looking for the Camera app.
Differences between music, video and photos again seems to emphasize their very different bodies of users. They actually do very different things because they service very different needs—people who buy music in iTunes or pirate it (as opposed to using Pandora, etc.), people who buy movies in iTunes or pirate them (as opposed to using HBO Go), and people who want to show their photos to someone. None of these use cases require personality and it seems like putting personality in a software icon meant to be universally understood is a bad idea.
The change to the camera icon makes a lot of sense if you've ever watched a first-time phone user looking for the Camera app.
Differences between music, video and photos again seems to emphasize their very different bodies of users. They actually do very different things because they service very different needs—people who buy music in iTunes or pirate it (as opposed to using Pandora, etc.), people who buy movies in iTunes or pirate them (as opposed to using HBO Go), and people who want to show their photos to someone. None of these use cases require personality and it seems like putting personality in a software icon meant to be universally understood is a bad idea.