simple:
1. the ability to "hide" the native apps that i dont use, like stocks, weather, NEWSSTAND,...
2. with one swipe up, i can close all my background apps (in the application switcher);
3. with a swipe down, i can close any specific app (in the application switcher);
4. the ability to ignore/hide app updates (when they no longer support your device or iOS);
5. customize gestures for a given task. like replacing the home-button's function with a gesture;
6. camera: add the ability to do time lapse or a timer. You can even set a custom frame rate, aspect ratio and resolution while shooting video.
7. add the ability to make googlemaps the default maps app on the device;
8. i can backup and/or reuse all my saved games across all my devices;
9. move multiple items at a time, in the home screen;
10. transform my device into a hotspot with no extra charges, videochating and download heavy files (>20mb) through 3g...
11. attach more than 5 photos to an email;
...
im not talking about customizing fonts or stuff. i am talking about productivity and ease of use. simple things that speed up my flow and minimize my frustration. cheers.