At our band practise days I quite often find several of us singing along, myself included, even when I'm widdling away on lead guitar. This is really great as it creates an impressive background to our main vocalist wailing away. This set me thinking of something I'd really like to see in a future game: backing vocals for bonus points.
While we'd have our main vocalist scoring the big points, I'd love to see support for additional singers to score a few bonus points by singing along at key points in the song. Obviously we all need microphone stands and some means of plugging in multiple microphones - or maybe just use wireless Lips sets - but it'd add to the immersion I thought. Probably wouldn't work when comparing scoring bands for comparison as those without the complete band setup would lose out.
Of course this lead me to wonder about duets. We've tried plugging in a second microphone and also having two singers share the same mic but it doesn't work since it confuses the game as I recall. This would be slightly different to vocalist tug of war, but would be great for songs with dual vocalists, such as Lacuna Coil. Singing really isn't my main thing, but I enjoy singing along while I'm doing the real work in the band...
Not overly important by any means, but it'd tickle me I think.