P: Add a keyboard shortcut for opacity for pressure and size for pressure

Yeah those exactly. There actually is already a shortcut for Airbrush mode I think

Do you mean the buttons in the paint tool options bar: "always use pressure for size" and "always use pressure for opacity"?



How about "airbrush mode" as well?

The mixer brush does have a precedent for keyboard shortcuts for some of the tool options (beyond opacity/flow and blend mode).