Like @steffenr said, selected mix blinking will not be a solution to this problem I think.
Anothers brand use a good way to show us we are working on mix:
– all mix light on / blinking the selected mix you are working on.
– all mix light off when you are back to your Main.
But I like this idea of « mono color » for channel strips too. And it could be the color of your selected mix channel strip.
Sorry once again for my language!