more independent voices, please
In my experience, it is traditional to write guitar music on a single staff. As a composer / arranger for guitar, I have been thwarted by the four voice per staff limitation, especially when notating finger-style and finger-picking arrangements. Not being polydactyl, I've never needed six voices, but I've certainly needed five.
The four voice limitation forces me to use a grand staff, which guitarists find hard to read and which doubles the page length of a score.