I wish we have the ability to download the keyboard separately. Because sometimes we like the theme we have & we just want to change the keyboard. I wish this feature was available for like the notification panel. I know we have the ability to design our own as of now, but we are limited!!!
If you mean change the color scheme, keyboard keys functions, text and icons colors, etc, then Microsoft SwiftKey will do this and much more. I use it and have even before MS bought the app right a few years back..
