The use of keyboard margins will become more crucial to keyboard ergonomics with the current advent of diminishing bezels on the latest Android smartphones. This will have two major repercussions:
1: smaller bottom bezel will drop keyboard below comfortable position since hands still need to hold devices nearer towards middle
2: slimmer side bezels will mean fingers need to reach further towards palms to reach the furthest keys
The use of 4 adjustable margins is being proposed to replace the current system of fixed keyboard sizing. Adjustable margins would also tackle keyboard ergonomics on bezel diminished devices as it would allow users to size and place keyboard into a comfortable position. With bezels now shrinking on many new devices, there now needs to be a large bottom margin underneath the bottom row, and left and right right margins would keep thumbs nearer to the centre of the keyboard, where thumbs can reach with less strain. Adding the top adjustable margin would allow for key size adjustability to suit the varying finger lengths of users.
For an example of a 4 margin keyboard, please see the current Samsung keyboard for its S series devices. The Apple iPhone X also demonstrates the need for a large bottom margin for phones with little bottom bezel.
Thanks. I know you guys get quite a lot of flak on these forums, but it's clear you are endeavoring to deliver the best product you can deliver. Your efforts are at least appreciated by this user.