I'm not sure how useful this would be, or if it's even feasible, but what about a dynamic routing diagram? It would display the actual (specific) signal path of a given channel strip from input to output and all the bifurcations resulting from busses, signal processors, synths, etc. It would be launched by clicking a specific point on the strip in the console view and displayed in the MultiDock.
What I'm describing is not a 'passive' schematic diagram (although that might also be valuable), but rather an 'active' diagram that indicates where non-zero signal is present (perhaps denoted by a red highlight). It would show the current state of all faders, buttons, etc. that modulate signal flow.
If you really want to get fancy, it might include something akin to an oscilloscope probe that you would stick anywhere in the signal path to display the signal waveform.
Having a dynamic visual representation like this would be useful if:
1. you want to obtain an overall view of a channels' structure (to verify that your signal path is what you think it is)
2. you're troubleshooting a problem (you could display this diagram to see where your signal stops)
3. you want to compare the signal flow in different channel strips side-by-side
4. you want to share your signal path with someone for educational purposes or to get help diagnosing a problem (e.g., you could post a screenshot to this forum)
Cheers...