Add object > expand to contextual taskbar / make it possible to add other buttons to the taskbar

Suggested feature: add an expand/expand appearance button to the contextual taskbar in Illustrator. This is one of the features I use most, and it would be so handy to have it right there in the contextual panel when dealing with shapes/strokes/text.

It would also be great to be able to edit contextual panels to add buttons ourselves.