changing the layout on the fly
Use of hotkeys which you can design on the iPad keyboard with which you can change (a selection of) the layout of the iPad keyboard on the fly during gaming.
I want to be able to change the layout in reaction to certain gaming circumstances.. for instance if i get into a fight i want several buttons for fighting on the right, but if I later for instance want to plow my field of crops then i want the fighting buttons changed into buttons usefull for a farmer..

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Mick commented
Adding to this, the option to combine the following two suggestions:
There are many instances in games and other applications where you may want a button to show a new window or swipe to a different window (eg. Elite Dangerous nav/targetting windows)