I recognized the given name of her character, but couldn't be bothered trying to remember who she was or anything, since I figured they were going to mess it up anyway, so I'd wait to see what she did before making the comparisons. I think I was just assuming she was one of the women hitting on Rand at the party ITB. But when I saw your mention that she's of House Damodred, I remembered it from New Spring.

So that means they are almost certainly going to start playing with the datum that Moiraine is related to a lot of political players. From a strict plot perspective, that's utterly superfluous, as it does not come into play at all. From a character perspective, it's huge because Moiraine utterly renounced her family ties. She does not sign her name as Damodred even on a letter she intends be received as her deathbed declaration and final testament. She tells Thom that she does not identify as a Damodred, and is rather credible in that statement since it is in the context of flirtatiously letting him know that she is aware he murdered her brother. Part of Moiraine's PROBLEM is that she was raised by House Damodred, and given a full dose of their rationalizations and justifications for all the things that gave them a "decidedly unpleasant" reputation even before they got the country trashed by the Aiel. Removed from that environment at a relatively malleable age and indoctrinated into the White Tower perspective, we have the explanation of her patterns of behavior and difficulty connecting with the Emond's Fielders. She might have rejected her family's methods, but there are still artifacts of their mentality in her thinking, which is why she is so ruthless and plays things close to the vest, and poisons the well with Rand, Perrin and Nynaeve, and when she finally gets into a mentor relationship with Rand, spreads her affliction by teaching him politics, instead of governance and leadership. She is doing what she thought of Thom doing in Tear, settling Rand down for a political job, when he has a much higher purpose. She was right that Rand is for the world, not one country, but just replicated the error, in thinking that he has come to adjudicate political disputes and rearrange the deck chairs on the Titanic, instead of saving the world and building a figurative ark. Because Damodred. She might know that they are bad, but doesn't get how they are wrong.

It's the most amazing backstory in all of Wheel of Time, she's basically this story's version of Boromir and also Tyrion Lannister. She's a powerful figure in the fight against the forces of evil, who fails to recognize that this mission is not like all the ones that have been fought in this age so far, and they are not going to beat him by using power (political or magical). And she's the diminutive renegade member of the most evil aristocratic family in the setting, who, despite trying to be better and resenting her family's heritage, can't help perpetuating the cycle in her own way.

And they are going to fuck it all up so bad. They don't get how she's Boromir, they think she's Gandalf, and rather than accept that she's Tyrion, they're going to try to make her Galadriel as well. I can see no other reason for casting a known actress to play Moiraine's sister, who never appears in the books at all, unless they are going to make this all about Moiraine being a Cairhienin noble. Fuck!

The books did not even acknowledge the relationship between Moiraine and Elayne. In the same book, a few chapters before it is explicitly stated that she is the sister of Elayne's father (so you know it can't be a world-building datum that Jordan failed to work out when writing the characters' interactions), we get Elayne's PoV in a discussion with Moiraine, where she even contemplates Moiraine's childhood. Later, Moiraine is thinking about Elayne and Nynaeve heading off to Tanchico on what she thinks is a bullshit mission to a very dangerous city, and she is basically rationalizing her role in pushing them to it as necessary and soothing her conscience with the idea that Thom can keep them safe, that would have been an ideal point to note that Elayne is her niece, to emphasize that ruthlessness she is displaying here, and her focus on Rand and the mission to the exclusion of everything. But it does not come up, because they are not aunt and niece in any sense but the biological (also, pre series, Moiraine has encountered Elayne close enough to fully assess her channeling potential, so it's not like this is their first interaction). Elayne is desperate for family relationships, to the point of formally or informally adopting substitute siblings everywhere she turns, and shipping every one of her female friends with one or another of her brothers, but there is nothing for her and Moiraine, because the Trakand in-laws are the healthy tissue she had to amputate to rid herself of the Damodred gangrene. And it's going to be "Aunt Moiraine" every time Elayne addresses her.

I hate these writers.