I think exterior walls need one more layer! EXTERNAL Insulation. It would go outside of the sheathing and inside of the cladding air gap.
And now that I think about it, the air gap could use a bit more detail. The exterior insulation I plan to use recommends 1x3 (nominal) vertical battens outside of the insulation, oriented vertically, centered on the stud centers and spaced same as the studs - and they will also function as the air gap spacer! Not sure what other options there should be.