Transition from glossy to matte UI elements
Something I noticed as a general trend with modern technology (especially in mobile development) is a trend away from shiny, glossy UI elements like icons and buttons to a more flat, conservative style.
Here’s a really interesting discussion I found about the subject on the UX stackexchange site http://ux.stackexchange.com/questions/35576/what-explains-the-current-shift-from-glossy-uis-to-matte-uis
Looks like the main culprits would be Windows and Android, while Apple seems to be sticking with what they know (for iOS at least).