The balance of evidence is indeed on women serving, in the late 23rd and mid-24th centuries alike, except for the anomalious occasion of "Redemption".
Which is based on this single bit of dialogue, never revisited or otherwise supported:
Picard: "And who speaks for his family now?"
Gowron: "Lursa and B'Etor, the sisters of Duras."
Picard: "And they would claim the leadership of the Council?"
Gowron: "Women may not serve on the Council."
Gowron's answer appears a non sequitur of sorts: Picard asks about leading the Council, Gowron speaks of servitude. It seems out of character for Klingons to consider holding the top public office "serving"... Being Chancellor is not servitude in practical terms - it's superiority over those who serve. And nothing indicates that the Council Members would be power peers to the Chancellor.
Perhaps Gowron knows (but doesn't explicate) that it's impossible for Lursa or B'Etor to directly vie for Chancellorship (because although they inherited Duras in many ways, they didn't inherit all the special privileges, favors and political capital that made him eligible for Chancellorship candidacy), and that they would have to work their way up through the ranks, like any other Klingon, by first becoming Council Members - a path blocked from them by the current legislation?
But never mind that. The dialogue confirms that Lursa and B'Etor specifically cannot be on the Council, at least not in the role of Chancellor. They might be special cases for "women", but if women in charge of their own Houses can't serve/lead, then it appears unlikely that any other women could, either.
So my money is on the legislation changing. Klingons apparently aren't big on written law anyway; they probably rewrite their rules as often as they rewrite their history, because the sword remains mightier than the pen.
The other option is that Gowron's word "women" in this case carries a special meaning that only applies to the Duras sisters. Possibly women who ascended to House leadership through no action of their own, simply by having the House run out of male heirs, are specficially prevented from grabbing power? That'd make some sense: DS9 suggests the Alpha Female holds extraordinary financial powers, and it would be bad form to allow those to combine with political powers unless the female in question gains the political powers through her own Klingonlike action (that is, she slays her worthless husband or something). Lursa and B'Etor would be ineligible for Council positions exactly because they held ultimate power in their House now, and there'd be a quarantine period or a requirement for them to demonstrate "true" leadership before they could apply - things that a
male heir would never face even if he ascended to House leadership by similarly honorless/honor-neutral means (say, Mogh ascending because somebody else killed Worf), because a
male would not carry the compromising additional financial powers and thus would not be a threat to the power balance.
Pretty convoluted, and certainly not preferable to the legislation simply changing, but that could be a Klingon way to see things.
Timo Saloniemi