I'm going to give my opinion on the quackers from the perspective of someone who has been rping on NWN for the past 5 years.
First off, I've never needed a typing indicator to tell me to wait for someone to finish typing or to give them space to continue typing. I simply type what I want to say, and if it's something long, I break it up into a few digestible bubbles. When I'm done typing, I pause and give my partner time to talk.
If that person is afk or tabbed out, I give them 5-10 minutes to come back or finish typing, and if it's longer than that, I send a polite tell.
I think that the typing indicators weren't really a needed change or something that the average player asked for. I think that the system as it is, if it's going to remain (which I assume it likely will), should be opt in, rather than opt out.
There are people who have a few concerns of abuse, or citing concerns about anxiety or feeling pressured. I don't think the quackers are a good accessibility tool for people with anxiety or ESL problems, if this is what this UI update was envisioned to be. I've always been met with courtesy and respect if I type slower in certain situations, and anxiety about typing has always existed with or without the quackers being there.
I suspect that for some, the quackers will add on to the pressure of feeling like people are waiting on for them to respond rather than giving them time to type. I'm not sure if people will take advantage of the quackers to abuse, it's not outside the realm of possibility, but I'm not sure how common this might actually happen in practice.
My concern is about how these quackers will inherently change the server culture in terms of brevity and how we treat one another. People have already started trying to pressure one another to make use of the quackers. I've heard people also report that the flow of roleplay has also begun to slow down in large group roleplay, and I'm concerned about whether players will start to pressure one another to stick to the concept of 'posting orders', that I've seen done in other roleplaying mediums such as World of Warcraft, and Conan Exiles servers (I think this is a very toxic concept and disrespectful of people's time, because players will scold each other or treat each other poorly for speaking outside their turn and it make roleplay encounters very, very slow). I'm also concerned about whether or not people will start to hold it against one another for not making use of the quackers, or the perception that people aren't willing to wait on one another to finish typing will fuel resentment, because as much as we might like to think that most people we meet are courteous, people will also be petty, and this HAS started to already happen.
One of the biggest things I enjoy about Neverwinter Nights roleplay is how quickly roleplayers respond to one another and how conversational dialogues are overall. The manner in which the pace that roleplay occurs has been unlike any other game or medium that I've experienced before, and this makes Neverwinter Nights unique. I've never really experienced people that type very slowly or find it a hurdle to communicate because of this (maybe when there's a dungeon happening and things are moving very fast, I've experienced that before many many times). I've also never felt pressured to respond if I am typing slowly. More often than not if there's a concern for ESL or disability when writing, I've had players respectfully communicate that to me OOCly and ask for patience, which I am more than glad to give for them.
