You can’t stop, you have to keep running. This same rule applies for IT world. Whatever software you made. You need to keep it updated. Not only from security threats, but also the latest design you need to provide. Google is doing same for Android users. Android 4.4 KitKat was a great jump from Jelly Bean. But Google is thinking new for Android 4.5. Where Apples iOS7 is on mark to give silk smooth os experience. Google is tring to that on Android.
Here is a leaked screenshot of Android 4.5. You can see the lots of minor changes in 4.5 respected to 4.4.
Here is a nice infogram in which you can check how Google changes the icon on Android OS.
So day by day Google change the icons of Google Apps like Gmail, Maps, Google+, Play Store etc. As icon draws your attention first. Hope we will see more changes in Android 4.5