I would like the see the possibility of being able to map any function to any button/controller/input device, and not have mandatory modifiers (like CTRL) for some functions. Also the 'hidden' functions like the mirror position I would like to map to any input. I use a buttonbox and a separate keypad, and like to make best of both. For example : It's a bit annoying to change the position of the mirrors when being forced to use CTRL and ALT only in combination with the buttons that are assigned to the seat position.
I use a phone app that acts like a button box and I can combine the extra keypress like CTRL with other commands so I have virtual buttons for mirrors and seats. I adjust those only when I'm not driving so having an actual physical switch isn't a high priority for me. (Roccat's Power-Grid)
Maybe try joy2key: https://joytokey.net/en/ - i am using this for my button box to map all functions which need several keypresses to it
I have used that program. But like most, I run many sims. Plenty of tools to setup... This is a wish that should not be that difficult to implement for Studio 397. A new GUI and improved keybindings are in the same department...