Reduce the height of the keyboard on iPhone
I really like your iPhone keyboard but suggest that you look to reduce the height to the top of the QWERTY row to be the same as the standard iPhone keyboard (or even a little smaller). Right now the main Keys are higher and it means your keyboard takes more vertical space than it needs to, affecting usability.
Taken a bit further, it would be lovely to have a "slim keyboard" option to reduce the total height to match the standard keyboard.
“Short mode” now available in portrait orientation as of release 4.5.3. (Set independently in portrait and landscape.) In short mode the keyboard is shorter than the stock keyboard.
Please note, you should remove the iOS shortcuts bar (under System Settings | General | Keyboard) for maximum space efficiency.