And it's interesting that some of the dialog between Susan and the Doctor no longer makes sense, because of regeneration.

Which parts? *curious*

Also, do go back and watch The Aztecs; it took me a few tries to get into it as well, but it's amazing ♥ (One gets engaged!)

Other stories I love:

One: The Romans
Two: Tomb of the Cybermen, The Mind Robber, The Invasion
Three: Terror of the Autons, The Daemons, The Green Death
Four: City of Death, The Stones of Blood (& others from the Key to Time arc), Horror of Fang Rock

Yay, I love it when people start watching Classic Who! :D