Being able to customize shortcuts would be incredibly useful, but if that is not posible then a Mixer brush shortcut would be nice, I use the Mixer brush quite often, and I also use the eye dropper as often, however having a shortcut for the eye dropper seems redundant to me, as I have to touch the screen again for the mixer brush, so I had an idea
Have the Alt/Option key change the shortcut thing
B : Brush
Alt+B : Pixel Brush
Alt+B * 2 : Mixer Brush
Alt+B * 3 : Colour replacement Brush
And if the "- * 2" or "- * 3" cant be coded in, lets instead use the other keys we have, "alt + shift + [key]", "alt + ctrl + [key]", "shift + ctrl + [key]"
Thank you