--unsigned doesn't do anything

[unsystemizer]

 --unsigned            print out unsigned hex of transaction; do not sign or
                        broadcast

It doesn't do that, it just makes the entire action silently fail (nothing is returned at all).

[unsystemizer]

It looks like it was disabled for some reason: e9266b8

[chiguireitor]

If this was removed and still lingering on the cli, it's better to remove it altogheter.