Thought of a new one, an option to make the colored outline of your brush be the same as the selected color you have chosen (cursor matches chosen color, swaps to color picker when holding Alt down to show the dropper appearance). This would make matching my color picks before laying a mark, sometimes even when you color pick you end up with something that is slightly different than what you meant to grab and don't notice until you make the mark, this would reduce that unneeded mark making and undo'ing quite a bit. This is another thing that coupled with the one button tap color picking would make my entire process infinitely faster.