I think most fans completely underestimate what an outstanding cliffhanger "The Time Meddler" has. It's easy post-Time Lords to remember this one as "the first appearance of another Time Lord" - except at this point there were no Time Lords. Steven and Vicki enter the crypt and HOLY SHIT THE MONK'S GOT A TARDIS. It must have blown the audience's mind. It is such an unexpected twist.