Why isn't ANET repurposing Dungeon NPCs?

It boggles my mind that we didn't see more of Scholar Yissa during LW3 (she is the mursaat researcher). She could've been put at least in ember bay at mursaat fortress.

Another thing, Warden Illyra, researcher of Forgotten&Glint and actual first sylvari to ever repeat the Forgotten cleansing ritual. Such a wasted opportunity for PoF, but she could still be useful, maybe she could help try to convert Kralkatorrik like the Forgotten tried, or help Aurene take over his power, or something. She has the knowledge now.

Randall Greystone - last time seen at a bloodstone shard, turning into ghostly form and telling us he's going to the Mists to meet the gods. So now gods left, where is Randall? Why was that one particular bloodstone fragment allowing that kind of transportation? That plot has a lot of potential.

Also while I'm at it, would be cool to finally get the reforged Magdaer into the story somehow. Poor Eir died for nothing. Basically ANET writers are good at starting stories but they never finish them, it's frustrating.

They actually did bring Randall back, slightly, when dealing with the Burden of Choice / Shadowstone subplot:

It's possible, but I am hardly an expert on the seers. Luckily for you, Tranton Hainsworth is. He was trained as a novice by Randall Greyston. He's in the library across the hall.

https://wiki.guildwars2.com/wiki/Ogden_Stonehealer#Dialogue

But yes, more dangling plot threads. They're hanging out with Malyck, Bauer, and Chrysanthea.