It would be super helpful if we can make the solo to blend-in some of the contexts at a quieter level. So when I solo, say, the vocal I can still hear a bit of the mix so I don't go south with my tweaking. This is like turning the solo button into a focus button.
How loud the blended-in signal should be? This better be configurable to the user-preference, let's say the default value -18 dB, which mean when I solo track X all other tracks dropped down by -18 dB. At 0 dB the Solo should function as usual.