Startup sounds lovely. Could see that replacing the Rosie in my skiff. If I understand it correctly, though, signals are either fully left, fully right, or center.
Tangentially, I was going to build a Spring Reverb, but if there's a second revision coming up, I'll happily wait a while.
I like this a lot, and think having it as a separate module, like the NLC module that @Larrea posted, would work well. I wonder if it would also be useful to allow the knob/CV to invert the pan, making left right and vice versa.
Anyway, I reckon I'll try prototyping this fixed panning mixer idea, see what it feels like.