We would definitely love to add support for more gestures eventually! It is one of the challenges we face, however, because we're not entirely sure yet how we can implement them. The ones we did implement (zoom & pan) were implemented already by Godot itself, so we didn't have to do any extra work. We'd love to also implement palm rejection, but it's one of the other challenges we face.
By cancel and return, are you referring to undo and redo, or are these different gestures?