Why are we discussing anything? We do we discuss the Qunari with IB? The Wardens with Blackwall? The mages with Vivienne? The Fade with Solas? Spirits with Cole? It's a topic of conversation with a character. Since this is a video game and dialog is at a premium, said conversations will usually revolve around what makes a character different. The vast majority of your conversations with Dorian are about Tevinter and his project to reform it, why's he talking about that?
I mean, strip the context, and most of the above could be seen as real life issues. The Qun is about despotic, orderly societies, which we have in real life. The Mage debate has often be seen as similar to the gun control one. The Wardens and their modus operandi as secretive watchdogs with little accountability is very much a modern issue, too, come to think of it. Dorian's story of being the black sheep who wants to reform is society is not the most original, but it's a well-established story trope too, with echoes in real life politicians who want to enact sweeping reforms. The context is what makes those stories part of Dragon Age in the first place. Strip the context, and The Count of Monte Cristo is just about some guy going overboard on his revenge. But it's more than that in the end. Context matters.
I mean, I'm not blind, I know Bioware has social issues dear at heart and writes accordingly. But I personally don't find it egregious or overly preachy. It's not like they pester you with those things all game long whenever you like it or not. Whereas I could cite a few games who do hammer their points on the player with far less subtlety.
Mages and Qunari and Wardens all rely on the context of Thedas. They don't exist in the real world. Their form is lore-specific but their themes are not. That's what stories do - they explore shared human themes, which can be anywhere, but in context-specific forms, which is how those themes hit you harder. Not only unique forms but unique stories.
Simply talking to Dorian in his library - while they are the best Skyhold conversations in the game - are not side quests. I like Dorian's wish to reform Tevinter but I don't see that demonstrated in interactive content. Instead of using his quest time to explore his context-specific character motivations, such as reforming Tevinter or whatever, we focus on his personal family situation? Iron Bull's side quest is quite lore-specific, dealing with the Qunari's offer to ally with the Inquisition. Cassandra's got the whole issue with the Seekers, which is well enough. Solas is - well, he's just a can of Thedas-specific worms, of course. Cole's side quest is awesome. It combines spirit stuff, mage stuff, Solas stuff. We've got Varric and the Deep Roads and red lyrium stuff. Sera .... I don't like Sera and her side quests are awful, but I guess it's classist/nobility stuff...? *sigh* She was awful too, tbh.
Dorian? meeting his dad in a bar addressing his identity. What is that?
I mean Jacob and Miranda had daddy issues too but Jacob's side quest was a huge level involving a ship on a wild planet for ten years, if anything it made us think about marooned space ships, which is cool on a lore front. Miranda's side quests were enormous levels as well, full of mercenary groups and tours of futuristic warehouses and.. I don't know... lore-specific content.