Ach. You know, on the one hand, I kind of like those romantic notions of ancient female goddesses and a golden time in which sex was without shame.
After all, the shaming of sex is a bane everyone in the so-called "west" feels. (And probably everyone else, too.) As far as religion goes, a strong injection of feminine divinity, along with a more healthy attitude towards our physicality is surely called for and sadly missed!
The Hopi, the Germanic tribes, Babylon were frequently suspected of having employed matriarchal systems. In general, the idea of an ur-matriarchy seems to stem from the 19th century.
But on the other hand, we have precious little evidence that there ever really was a powerful matriarchy in place. Much less a matriarchy spanning the whole of humanity. True, temple prostitution did exist - but whether those prostitutes actually held a lot of power is quite doubtful. True, there are lots of little statues of fat women with huge breasts - but are all of them objects of reverence, do they all represent The One Female Goddess? (The reduction to One God, whether male or female, might be seen as patriarchal by many a feminist, by the way.)
From what I've read so far, we have only very little evidence of actual matriarchies. When you read the article I linked, which is fairly typical of the... shall we say "spiritual" reading of such hypotheses, it's a mesh-up of second-wave feminism, thinly veiled kinky eroticism, and new-age eclectic spirituality. It takes everything it can find, by way of free association, and attempts to create a myth from it.
Charming, but hardly scientific.
Moreover, there is often a kind of scientific conspiracy theory going on in those articles. Because female history has been hushed up by patriarchal historians, therefore every little sign of female activity is a hint at an overarching matriarchy. It's just bad science.
It's a compelling, fascinating, enthralling fantasy. But, for better or worse, that's all it is.