More microtuning support
I hope MuseScore 4 will add the functionality of automatic, global microtuning. A basic implementation is to allow the user to set the fifth size in cents, or set the number of equal division of the octave so that it can compute the fifth size in cents. It should also compute the values of sharps and flats and apply the tuning.
Another important missing feature is to create new accidentals by combining existing ones. Some of the accidentals in the palette are meant to be combined. It'll be great if it allows the user to set the value of each accidental and then automatically, globally tunes it.