I find that once I amass a ton of tracks, and I'm soloing tracks to hear out they sound together, I sort of "forget" where everything is since the way they appear in the mixer don't always correlate with the way they appear in the sequencer area.
I noticed when you solo tracks, the levels are only monitored (in the mixer area) on the soloed tracks. The levels bounce up and down, colored green. I thought it'd be cool if for the tracks that are muted, you could still see the levels, but instead of being green, they are grey. That way, you know where the other parts are coming from, so you can easily unmute other parts to slowly bring them in.
Of course, you could just use the sequencer area to do this (it's easy to tell which part has audio playing at that moment), but when you're really interested in levels and sort of trying to mix everything together, you're probably going to be interested in looking at levels and won't want to use the sequencer area as much.
Hmm, I had a hard time explaining that.
Bottom line: sometimes I feel lost in my own song, because once I mute a track, ALLLLLLLLL the other tracks go black, and I don't know where anything is. So as my song grows bigger as I add more tracks, progress slows to a crawl because I just get lost a lot.
I could do a image mockup but I hope everyone can visualize what I mean based on this bad description