To keep the UI clean, perhaps future expansions of extensions/embellishments etc. could be under a drop down list called “Advanced”, or perhaps a radio box you click that turns on/off the extended interface. Some additions that would be useful:
- turn any chord into any type of seventh (ability to tack on major 7th, minor 7th, or diminished 7th)
- ability to tack on 9ths (b9, major 9th, #9)
- ability to tack on 11ths (b11, major 11, #11)
- ability to tack on 13ths (b13, major 13, #13)
- ability to invert add7, add9, add11, add13, etc. chords
- ability to invert sus2 and sus4 chords
- basically the ability to invert anything
- the option to add a deliberate, arbitrary slash note to the bottom of a slash chord
especially for a lot of jazz/blues-based tabs. Even if it’s possible to kinda hack together a major 11th drop 9 chord or whatever when you might need it through convoluted chord inversions/subsitutions, it really makes no sense to the reader, who might be someone on the piano or guitar or bass who just wants to read something like “Cmaj7b9#11(drop5) / B” and play against that instead of whatever else would have to take its place. Almost purely for a readability reason, honestly.