Will you critique my schematic, please?
what I'm really looking for is constructive criticism on the
  layout/design aspects of the schematic itself.


See how much room you save and how much de-cluttered it looks now: -



I've just basically cut and pasted in paint so there are a few bits left where they originally were.

As for the multiplexer this could look a lot clearer. I'd put all the pots vertical and to the right and rotate the chip so that its interface wires to the micro were not passing through 90 degrees i.e. make things simpler.