Possibility to change Tools without using mouse, I mean changing tool only with keyboard. For example: one click in "J" button run 'Spot Healing Brush Tool' but when you click 3 times "J" button you can use 'Patch Tool'
Most if not all tools in PS have shortcuts already. just right click and it will show them. by default they are used with shift. Like shift-b scrolls through the tools under the brush tool, "brush, pencil, color replacement tool, mixer brush. for the spot healing choices, use shift-J