Good point! She's one of the most immediately available of the Pilgrims: that is, we immediately get the sense that we know her and we know what she's like - and she's immensely confident in putting her opinion forth and speaking (note the way that the Friar, who interrupts her prologue, gets parodied himself at the start of the tale). The Wife - in claiming her independence, in refusing to bow to male control, and in the sheer number of husbands she's been through - is often seen as a proto-feminist (a feminist before feminism existed). But things aren't quite so simple.
With her five husbands, she's certainly sexually experienced, as Chaucer tells us:
In felaweshipe wel coude she laughe and carpe
Of remedies of love she knew parchaunce
For she coude of that art the olde daunce
She knew that 'old dance' and all its moves, the last line implies, and there's perhaps something slightly repulsive about the Wife - she certainly doesn't conform to the traditional idea of monogomy in matrimony. It's not just one husband who died followed by another: it's FIVE:
She was a worthy womman al hir life
Housbondes at chirche dore she hadde five
This is pretty extreme. How do we feel about the wife, who is up to her fifth husband? Do we celebrate her independence or do we judge her a little bit - do we think, in other words, that she might be something less than moral in a Christian sense? It's a bit of both.
The Wife's relationship to Christianity is also problematic: she constantly quotes the Bible to justify her point of view - but she misquotes it and deliberately bends and changes its interpretation to suit her own ends. She wants the Bible to justify her multiple marriages, so she quotes 'God bad us for to wexe and multiplye'. 'Go forth and multiply' doesn't seem to encourage multiple marriage if you read it in the text. So she has a liberal way with text (many of Chaucer's pilgrims do) and with twisting the truth. But, on the other hand, she is impressively well-read and learned.
As so often with Chaucer, it's balancing out the positives against the negatives.
You might take a similarly ambiguous view of her behaviour towards her husbands. She manipulates them on purpose: flirting with other men to make her fourth husband jealous (though he cheated on her first), and pretending to be dead in order to scare her fifth into submission. She'll do anything to gain power. In a feminist way, maybe that's laudable in a patriarchal society (one ruled by men); maybe we just think she's manipulative and unpleasant.
Speaking of money, I'm not sure how Chaucer wants us to feel about the Wife's capitalism. She even says at one point that her genitals have a value if she were to sell them as a prostitute:
For if I wolde selle my bele chose
I koude walke as fressh as is a rose;
But I wol kepe it for youre owene tooth.
Her 'bele chose' (her 'lovely thing', literally) is her genitals - and she's saying here that if she were to sell it... she could walk in clothes that would make her as fresh (attractive) as a rose. How do we feel about a woman exploiting her own sexuality as a monetary value?
One final thing. The Wife of Bath is a woman speaking through the re-told narration of a man (the Chaucer who is a pilgrim in the Tales) via the narration of another man (Chaucer himself). Isn't it a bit problematic to consider this ventriloquised man-woman a proto-feminist?