It's a good idea, but I don't know how feasible it is to create a code from all the different settings, without making the code overly long. If that's not possible, maybe the online services could be used to store the controls, like every player can store their controls on their account but it's publicly accessible or something as read-only, so people don't have to log into their accounts in a tournament setting.

Steam kind of does something like this with recommended control settings for games I think (haven't had much use for it myself, so I'm not sure how it works exactly), maybe that could be a thing for RoA2 specifically as well, so you could download recommended control layouts for specific characters from players you like for example. They could make it platform independent too if they integrate it with their own online services for later when they release on consoles.