Your bit about 'romantic fantasies of certain 19th century mystics' mystifies me. I can hazard guesses as to whom you are thinking of, and they actually have zip/zero/nada to do with Wicca. This bit - 'These persons, usually men, seemed to be interested in what they perceived as a more sexually permissive pre-Christian Britain.' is just plain insulting to those of us who practice Wicca and Paganism. And may well show a lack of understanding of what some folks were trying to do. May also indicate that you are mixing up Crowley's activities after he left the Golden Dawn with the Golden Dawn themselves, who actually AREN'T Wiccan (although Wicca does use certain rituals from time to time and group to group). They were merely trying to consolidate a Western Estoric along the lines of the various Eastern ones.
You say '"Druidic" rituals were the basis for initial "rites". To my knowledge, no wicker men filled with human sacrifices were ever burned alive. What was used was very selective.' Um? What? Where the HECK did that come from? Seems to me that you have in mind certain Roman propeganda (and by Roman, I mean ACTUAL Roman, not Roman Catholic). Romans looking to conquer Gaul and Brittania claimed such things so as to make the drain on Rome's coffers look necessary to the Roman population. Got squat to do with 19th century occult and modern day Wicca or Paganism.
During the 20th century, Feminists latched on to paganism, accusing Judeo-Christian-Muslim traditions as being patristic. At this point, "Wiccans" seem to have taken a definitely feminist tone. Insofar as I can discover, Wiccan covens today are universally led by women, and supported by a man, often their "significant other."
Is that a bad thing? While I question their ability to maintain the balance (God/Goddess, Masculine/Feminine) you make it sound horrid that some women actually DARED to solely worship a Goddess, and seem to think it's just a means of thumbing their noses at the establishment.
And if you utilized the internet and did a quicky search, you'd note that many a group out there does not fall along these lines that you have drawn.
There are solid historical basises for various Wiccan practices, but frankly, for me to give you proper examples, you'd have to be more specific in your question, since Wicca from group to group and practice to practice can encompass many different cultures, such as Egyptian, Greek, Roman, Teutonic, Celtic, African, etc, etc.
Remember that Wicca is a MODERN spiritual path. If you want to look into pagan faiths that attempt to reconstruct, you must go to RECONSTRUCTIONALST pagan groups, like Imbas (Celtic) or various Astru groups (Teutonic/Norse), Nova Roma (Roman), etc, etc.
I fear you have a rather cynical and pessimistic and not quite clear view of a VERY valid spiritual/religious path. And you've mixed up a great lot of stuff that has NOTHING WHATSOEVER to do with Wicca or Neo-Paganism or Reconstructionalist Paganism.