How about a setting that, at least initially, when adding a synth to the rack, the color of the synth matches the color of the tracks?
 
And any color change to the output track changes the color of the synth in the rack. 
 
And being able to change the synth color and have either or both tracks change.

And, any midi track that gets pointed to the synth inherits that color...
 
Regards,
Dan
 
 

I like...