it’d really need something faster than a pie menu button. we have so many shortcuts, though, that a button or indicator/widget/ clickable mark on the corner of the gizmo itself in the viewport would be better.
We already have ctrl, shift and alt shortcuts on the “o” key, right? if not, Alt-O (“alternate Orientation”) seems like a good one
Because then you’d have (obviously) an option on the settings to either always save the last used orientation, toggle between the last 2, cycle between the last 3 or always revert to global/local after the operation. Less menus,more shortcuts
supposing you chose “save last” option
(in the example, you want to make 2 local x grabs then a global)
starting with global orientation
shortcut to change the orientation (a click or 2 buttons)
GX
GX
shortcut again
GX