So... whats your solution, o wise one?
Before I begin, I'd like to acknowledge that every action or reaction cannot be taken into account, and I prefer judging people as individuals and not as groups and I'm a "laws are meant to protect the lives of all a country's citizens regardless of status, and punish the guilty, regardless of status," kind of guy, but I know that many of those in power inevitably abuse that power, either to empower themselves or to keep someone else from rising up as it would give the illusion (or reality) of them losing that power. As such, there is not going to be a perfect solution to magically fix everything, so I'll simply highlight what I would like to see occur even though I know the nobility of Orlais, Ferelden, and well everywhere in Thedas, would oppose it.
To begin, forcing change upon the unwilling never works out. In order to make things for the better, culturally and socially requires a change of hearts and minds.
This can be accomplished through celebrating the accomplishments and lives of specific individuals, enacting, and enforcing laws that give true equality in the eyes of the law; the law must also be enforced regardless of political or social station.
For example, the Chevalier's in Orlais graduate by killing unarmed elves who happen to be out after curfew in the alienages. Such practices are discouraged already, but really only in public. This practice would have to end entirely. If you can't make the Chevaliers want to give it up (in Origins, Leliana says they are given a great deal of clemency for their actions in exchange for their services to the country) then you have to punish them every single time it does happen. Murder means death, so every Chevalier caught may face the hangman's noose.
Another thing would be heavy fines or possibly seizure of goods of humans who burn or destroy property of elves who leave alienages to build lives for themselves, to repay the elves who lost everything.
Either they wise up or they run out of Chevalier recruits...whom have to be noble-born just to qualify for training. No punishing them for existing, but only if they're caught abusing their power.
Giving positions of leadership to elves, such as Briala becoming Marquise of the Dales, would also be a boon, if a riot or assassin doesn't kill them first, in that long-term, elves are seen more and more as closer to equals to humans than second-rate citizens they are generally seen as. It's merely surviving the short-term that'll be the issue here.
Another thing that really only happens with Leliana as Divine as something I would like to see is elves (and dwarves and Qunari) be given places as equals in the Chantry. Mother Giselle says that although it is really political, the Chantry clerics do teach that elves and other non-humans can't enter the priesthood because they are further from the Maker than humans. So having them in positions of authority, moral, political, or even economic, so long as that power is not abused, would help in the long-term.
Although, again, surviving the short-term is going to be the issue.
Essentially, I'd like to see a Martin Luther King Jr movement for elves, and see them treated based on individual merit and not the size of their ears. If the games don't let me change Thedas to that end, at least I can roleplay an idealist reaching for these more modern views of society. Forcing change on the unwilling has never been peaceful in the history of the world, real or in Thedas, but changing hearts and minds, although much slower, has real life examples of being effective.
It just requires those in power to give a darn about it and be willing to act, and keep acting despite opposition. I don't see the existing power structure in Thedas doing that, so I'd like to put those who would try in power and then try and keep them alive long enough to get a plan going.
And for the record, I think Leliana tries to change way too much way too fast. I like Mother Giselle's response when asked why she doesn't take up the fight. "We have seen the chaos from trying to fight too many battles. I do what I can, where I can."