Slider too Maximize and Minimize keyboard size
How easy would it be to have a size sliding option just so users can size the keyboard exactly to their hand size? This way it could possibly reduce all the over all hand and finger muscle injuries in the long run. The medium, small and large options work well, but fine tuning would be perfect. Then with the majority of smartphones going towards a 80%+ screen to body ratio, that option could possibly help as well.