Hi--I just joined the forum and I was actually thinking of starting a thread on this same topic!
Mostly, I'm curious as to how other Tarot users/researchers view her reconstruction of history. I'm about a third of the way into the book, and I'm highly skeptical about all the connections she makes. Goddess-worshipping Gypsies brought sacred Tantric knowledge from the Orient (what a loaded term!) to Europe, where it was snapped up by Gnostic sects and Knights Templar and assorted other heretics?! It seems a tad implausible, to say the least. I don't think it makes Walker's understanding of Tarot any less meaningful, because I do believe there are multiple significances and connections in Tarot that may not be immediately apparent to the casual observer.
I'm coming at this as a student of culture, folklore in particular, plus I just took a course on Representations of the Roma in Western literature, film, and music, so right now I'm particularly attuned to how Gypsies are used by others who want to project their own ideas onto them as a convenient "look at these mysterious traveling folk!" trope. Walker doesn't cite any authoritative sources on the Roma--not that there are many, as the Roma are incredibly diverse and there haven't been a lot of studies made by insiders to the group, mostly it's been outsiders dazzled by their supposedly free and romantic lifestyle.
But while I'm reading Walker with a skeptical eye toward her history, I think she makes a number of intriguing connections between the meanings of the cards and the cultural climate at various times in European history. Her bile toward the repressive and reprehensible actions of the Church is understandable, and it's where she relies on the writings of the Church, ironically, that I think her scholarship is the strongest. What I think makes Walker's work truly brilliant is that it's not simply reactionary, that is, she's not just reclaiming a pagan heritage from the grasping claws of patriarchal Christianity--rather, she's fused diverse belief systems and alternative historical accounts to create a unique and meaningful approach to Tarot. I think her deck is gorgeous too, though I haven't begun to really work with it.
I guess what I'm saying is that I like her symbolic system, though I believe that her interpretation of historical data is not the only interpretation one could make of the existing evidence.