From Darkness, Light

After completing this quest, if you walk into the waters of the Dawnwell, you'll be teleported back to Silvermoon City. When you return, the phase will be changed, and all the elven dignitaries will have left. This means you'll miss out on the 'Stay Awhile and Listen' off to the side between Rommath and Umbric, like I did. Don't be like me.

I suppose I must now wait for the inevitable WoWhead front page article about that missed conversation.

There are some "Stay a while and listen moments"

Arator and Liadrin
Arator: With all that has happened, we haven't had much time to talk.
Liadrin: What's on your mind?
Arator: When the attacks first started, you went to the Sunwell and prayed for a miracle. Heroes from all over the world appeared in a flash of light just in time to save the city.
Arator: I don't understand how it happened.
Liadrin: I've never experienced anything like it before. In my desperation, I swear i could hear a gentle voice... "Don't be afraid," it said. "I am with you."
Liadrin: And there was... music. Like a song ringing in my heart.
Arator: Like the Radiant Song?
Arator: Could the voice you heard have been the Worldsoul we've heard about? Could it have reached out through the Light?
Liadrin: I truly do not know. Whatever it was, it saved us. I believe we will hear it again when we need it most.

Faerin Lothar, Andin, and Velen
Faerin: So, Anduin, why do you keep stealing glances at the esteemed Prophet Velen?
Anduin: He... was my mentor. He taught me so much about the Light.
Faerin: Oh, excellent! Then you can introduce us.
Anduin: Wait--! Velen. This is Faerin Lothar of the Hallowfall Arathi. I'm sure she's... overflowing with questions.
Velan: It is an honor, young Lothar. I, too, have questions. I hear tales of a large crystal of Light and Shadow?
Velan: We shall find time to speak at length. But first, Anduin. How does the Light feel to you now?
Anduin: Earlier, near the Sunwell, it was... overwhelming. I couldn't hear myself think. I understand how so many lost themselves in it.
Anduin: But now... it's gentle. The pleasant hum in the back of my mind I remember from my youth.
Faerin: It is wonderful you feel the Light so near once more, Anduin.
Velan: Indeed. So then, my dear pupil, why have you been avoiding me?
Anduin: This... I'm sorry, Velen. This is not the future you saw for me.
Anduin: I was broken. I'm putting the pieces back together, but they fit differently now. Some parts are just... gone.
Anduin: The Light called upon me, yes, but I'm still no great king. No true hero. I still can't even bring myself to abdicate the throne I don't deserve.
Velan: Ah, Anduin. You are young. There are many futures yet ahead of you.
Velan: But I will tell you this: in none of my visions did you remain idle for long.

Rommath and Umbric
Rommath: This new Dawnwell is a fitting tribute to our unity. Though, learning to live without the Sunwell's power may take some getting used to.
Umbric: Perhaps. Far more concerning to me is the Darkwell...
Rommath: It's no longer a threat to any--
Umbric: They were moving down through it, Rommath. You saw. Thousands upon thousands of void monstrosities... all headed deep underground.
Rommath: I... saw. What could Xal'atath be seeking at the heart of the world?
Umbric: Whatever it is, she used us to get to it.
Umbric: I fear her true invasion... is only just beginning.

As of today, this quest seems broken. Lady Liadrin doesn't appear to turn-in the quest.

Tried relogging and abandoning, flying back to Silvermoon to check around for her and flying back to the well afterwards - none of that works.

Maybe it has something to do with the new questline added today, but I have no idea for sure. There were 2 other players just idling in the area, including a gnome spamming question emotes at me, so I assume I'm not alone in having this issue.