I know we have the Ctrl+Z function for undoing something we didn't intend to do - (like deleting a note or a custom Guide) - both of which I have done.
But Ctrl+Z is sort of a "hidden command". Yes, you can discover it if you search the forums, but I think it should be more obvious.
So, I would like to suggest that Logos add an "UNDO" command - (to be typed in the command box) - which can also be dragged to the shortcut bar.
That way, when you need to "undo" some bone head mistake you've just made, all you have to do is click on the UNDO button on the shortcut bar.