I know that this probably isn't a super 'in demand' feature - but since SO recently included an option to have both seconds and bars marked on rulers simultaneously, I don't see it as too much of a stretch to include multiple tempi and time signatures measured out throughout a track (or even during parts of a track).
I like to do a lot of metric modulation and polyrhythmic stuff in my music, this option would make it much easier to practise, learn, write and compose/write using these techniques. I think this would win over a lot of experimental musicians across genres towards this DAW as well.