Or then K'ehleyr turned down Gowron's offer because it only covered him getting her a piece of furniture from the Council Chamber.
Really, let's examine what Gowron actually said to her:
Gowron: "What do you want? Command of a ship? A seat on the Council? There are many opportunities for you in the Empire."
K'ehleyr: "Opportunities that will present themselves only if you come to power. You talk like a Ferengi!"
Intriguingly, Gowron doesn't really offer K'ehleyr anything. He merely asks her two questions, then inserts some innuendo. K'ehleyr declines to take the bait, and that's that.
We can't be sure that it would have been possible for K'ehleyr to ever get a seat on the Council, or even command of a ship. Perhaps Gowron was saying that those two dreams were utterly unrealistic and K'ehleyr was being unreasonable - but that there were things that she
could attain, and allying with Gowron was the way to get
those things.
OTOH, K'ehleyr's response might well be taken as literally confirming that a Council seat or a captaincy would be things unattainable to K'ehleyr or any other female currently, but attainable if Gowron came to power and altered the rules.
If we assume that the lines of succession are in some way father to son in an extreme situation when the Chancellor is not killed by a Klingon in honorable combat, maybe Gorkon's supporters could have been pushed to accept Azetbur, especially if he set that up beforehand (he had to know assassination was a possiblity).
I'd argue that there
must be a rule that prevents random rabble from challenging the Chancellor - otherwise he or she would be swamped with duels every morning, and unable to get any governing done. To challenge a top leader, one probably has to already occupy the rung immediately below. A Gunner's Mate can't challenge the Captain if the XO has failed to challenge the Captain - the Mate has to challenge the XO first.
That is, Worf could challenge Gowron to a fight only if Gowron personally agreed to such a thing. Normally, Gowron could simply humiliate his challenger by sending him to face one of Gowron's bodyguards. But whatever Gowron was, he never was a coward who'd shy away from the demands of Klingon honor if maneuvered into facing such demands; and this once, he thought that a little show of traditional honorable conduct would be politically advantageous, whereas dismissing Worf would cost him massively on the political arena in this tense situation. Perhaps a leader in war is also more open to impromptu challengers than a leader in peace?
The idea that only the next in succession can issue a challenge to a leader would be consistent with much that we see, though. Azetbuhr need not have been merely Gorkon's daughter; she may also have been a prominent politician, or perhaps one of Gorkon's generals.
Timo Saloniemi