Thanks, glad it works for you now!
It would be cool to be able to just load in any midi, but it really wouldn't work, a lot of the time midis would just be mostly, if not entirely above or below whatever mid point was chosen, so maps would just end up being all 1 note.
Also, normal midis are often more than just the melody, they have the backing too, so it would either use all the instruments and the map would be a complete mess, or it would have to choose 1... somehow. The game would just have to guess which one to use, which there's not really a way to do.
And even then, the maps either wouldn't have any hold notes, or would have all hold notes, both of which would be bad.
There's going to be a big update to how maps work in the animation revamp, which will let mappers control Susie and Ralsei's animations, so even if none of those problems existed, the other notes will be used soon anyway.