Regarding your "Suprise Villains" comment Doug, a lot of movies had suprise villains, usually betrayers of some sort.
20th Century Fox's Sound of Music is probably one of the very first examples of a film with a suprise villain.
The younger audiences were led to beleive that Georg Von Trapp's would be lover, the gold-digger Baroness Elsa Schrader would be a key villain purely due to a) her status as Maria's key rival for the Geog's affections and b) her status as the potential wicked stepmother type to the seven children whom she had planned to send to boarding school once she got married. It was aparrent that she was only interested in marrying him for his wealth ala Lady Tremaine.
However the true villain wasn't revealed untill the night party where a certain party guest named Herr Zeller showed up gloating to Georg about something known as the Anschluss, again the younger audiences haven't a clue what's going on or what this "Anschluss" is whereas the adult audience knew exactly what was going on, while the younger audiences only just started to realize that the Nazis invaded Austria and not only is Herr Zeller is a Nazi himself but he's also the highest ranked official in the district, in short he's the Nazi tyrant trying to recruit Gerog Von Trapp into the Nazi cause despite the fact that Georg anti-Nazi and attempts to flee with his family to Switzerland.
My point being that the Suprise Villain Cliche you mentioned existed longer than you might think.