And here's a segment of the Wikipedia entry that supports Lee's subtext analysis:
Some episodes take a backdoor approach to such topics as racism, as seen in the first season episode, "The Witches Are Out", in which Samantha objects to Darrin's demeaning ad portrayal of witches as ugly and deformed. Such stereotypical imagery often causes Endora and other witches to flee the country until November.
Seriously, I recommend anyone interested in this series glance through the whole Wikipedia thread. It's a pretty fascinating look at the way TV shows got made back then -- i.e., in a sort of haphazard, half-assed sort of way.
For example, I don't think I was super aware of any cast changes outside of, obviously, Darrin. (I can vaguely remember a change in the Kravitz household.) But apparently there were tons more of them. And Uncle Arthur and Dr. Bombay played guest roles as mortals early in the series! That would certainly be confusing for anyone watching in syndication in mixed order.
Wikipedia also mentions the house, which was apparently modeled after a
Gidget set, and cameoed in various other series.