I think that Willow assumes greater authenticity in her lovers than she has herself. Though with Tara, she also knows that she somewhat writes on / about her and imbues her with meaning. But it's complicated, because Tara is also someone who Willow sees as mysterious and far above her and who intimidates her.

I don't think that's reading into it. I do think that, and this is weird/partial, but I do think that Willow is, by the end of the series, more transgressive than Buffy, in both positive and negative ways -- Buffy is the person I'd term as the better person, but Willow the more dangerous and POSSIBLY the greater symbol of hope; Buffy accepts power that's hers, Willow takes power that isn't initially hers and makes it part of her. I think seeing Buffy as being somewhere in the (relatively, compared to Riley and Harmony) recent past w.r.t. female power, subconsciously, makes sense. Of course, Buffy does have the power over Willow (to strip her bare) in the dream.