I think playing tunes in a different position on a five string just for the sake of it is kind of missing the point! Yes it does allow you to open up the fretboard somewhat, but a low G on the B string will sound a lot different to a G on the E string. Much the same as on a 4 string, if I want a 'dubbier' sounding 'D' for example as opposed to a D with more clarity, I'll play it on the E string rather than the A, depends what the song needs!
A 5 string (and any ERB) allows you more sonic options with regards to timbre of notes, not just positions and number of notes.
Si