The music system is still very limited in several ways. Most important, melodies are limited to the notes a specific instrument is able to produce, e.g. a pan flute has a more limited frequency range and a more limited polyphony than a lute. Also the shortest playable notes are still rather long, you may not be able to trust less than 1/4. The support of the MusicXML standard is so specifically limited that hardly any other scoring application is able to create compatible files, but editing in-game lacks a grade of precision and intuitiveness (e.g. you never know if a click will set the cursor, put a note, change a note, or whatever will happen).
And then there is another big flaw: As long as you did not powerlevel "Musical instrument" to a level of 100, you will have your melody slowed down by very annoying factors. And in addition, this slowdown makes powerleveling music quite impossible (I gave up after a level about 20). Talad himself said in a "Dev Q&A" session that he did not intend it this way. I would agree to a slowdown for maybe the first 5 or 10 levels, quickly decreasing though; limiting the length or complexity of playable melodies in lower levels is also a credible interpretation of a "lack of experience". The first approach was a mistuning, but that resulted in a cacophony, even at level 20, so no melody was recognizable...
I wish I had any clue about the work of a "Rules" developer; I have an own imagination about a balance between credibility and annoyance, but no information who would be interested in it and able to implement it.
