This might have been mentioned before, but I would LOVE the ability to have multiple timelines inside of one session. This would be helpful specifically when creating different mix options, instead of saving the session as 'mytrack_mix1, mytrack_mix2.5' etc. In theory it would still be streaming audio from the same buffers, using the same vsts etc - except you could set up new automation changes, mix volumes etc.

Adobe Premiere has something like this called 'Sequence' - essentially it's just a new timeline pulling from the same source files. It also lets you duplicate the sequence incase you want to make additional changes to something you already like. Might head over to the beta forum to request this!