As I recommend to everyone producing or mixing, I set my amplifier volume very high and then dial in how much dynamic range I'm shooting for with a (hardware) calibrated volume control. This way, I produce and mix with the song naturally sounding good and loud while preserving headroom in my mix for better mastering, all without having to look at the meters.
But for this to work, every track needs to be turned down, particularly virtual instrument tracks. -12dBFS or -14dBFS as a default would be great. Though a user-adjustable default would be best of all.
This is less of an issue in other DAWs like Pro Tools where a template session can have instrument tracks turned down in advance, but since instrument tracks in S1 don't get faders until they have an instrument, this isn't possible.
Please, please, please implement this feature! It will make S1 more attractive as a platform to engineers using this ideal approach. And if you implement it by default with a little note saying, "For best results, set amplifier gain high and mix with lowered faders", amateurs' mixes will sound better too.
Further reading on this approach: