I think Gardner put together a pastiche -- add a little ceremonial magic(k) here, a bit of folklore there, some chunks of what we DO know (not much) about ancient paganism... some typical male-female balance stuff (whether from Jung or Tao doesn't matter), etc. Did a very good job.
The wiccans I know (and I know a pretty good number) are really great and sincere people; many have "evolved" from the Gardnerian set-up originally. But yeah, I don't think the historical support is there, really. They tend to be lax about history, or not the most academically sophisticated about it. (Mind you, I haven't actually read much Starhawk or other of the more articulate proponents of wicca). As far as "personal revelation" I find many of them do think of themselves as psychic, or use divination methods they think provide something akin to revelation (even if only small ones). In essence they think it "works for them", even if not a "new dispensation" kind of revelation.
There's also this overlay of feminism which makes it appealing to many -- "the Patriarchical religions of the present era are toppling!" The appeal of this sort of thing speaks to real psychological needs, and bypasses critical functions in many instances. Which is pretty funny if you know much about Gardner himself.... but it has evolved past him, as I said.
Caveat -- this is all just from personal exposure to people, and only the most cursory reading of Wiccan literature. I'm sure Gardner or (especially) Valiente or Starhawk could be much more enlightening in a very few paragraphs than I can be in a longer essay.