You could have the option to implement both if you wanted. I think for those who want to use a keyboard then having the mouse for menu navigation would be the best course. But for those of use who want to use controllers then the mouse is not needed for that. I guess what I'm trying to say is this:
Keyboard config - keyboard + mouse
Controller config - Controller.
That's about it really.
Well there will not be a controller config. I will not go there because I don't want to deal with more complications. If a player want to use a controller I will include a joy2key inside the game folder or I will suggest a link to download it.
I used it and I mapped the keys of the keyboard to the controller and everything worked just fine.
There are 12 buttons that are used in the game. 4-arrows, Z,X,A,S,Q,W and Enter + Esc.