As can be seen here, with the title screen in the right pane, even if the proper romanization should be "Maoyuu", the official romanization is "Maoyu" with only one "u".
I don't think there's any technical issue preventing from us having both maoyu and maoyuu as aliases, is there? Since a great many people might only know the series as "Maoyu" (the way it's spelled on the screen) I think we should have that as an alias.
