You're thinking about it the wrong way.
You aim to help the elves to garner their support for fighting the Blight.
You cure Arl Eamon to receive a powerful voice in countering Loghain who is fracturing the humans. You must defeat him to unite them. Why? To fight the Blight.
Similarly,
The side quests have also never made more sense than they did in Inquisition. Why would Hawke go out of his way to help random people? Why would the Warden not fight the Blight when he only has less than a dozen people in their name? It's pretty much a constant suicide trip for the Warden. At least the Inquisitor has the whole forces and agents of the Inquisition to make stuff easy.
In Inquisition, you do those "side-quests" to spread influence and gain power for your Inquisition.
And I would love these quests if there wasn't Cory's agents or influence in all of 'em.
Why I think DAI's main plot is flat and DAO's is not? 'Cause DAO shows us the world that is much bigger than even the Blight.
Yes, we helped elves to gain their support to fight darkspawn, but elves didn't care much about darkspawn. They did care, they just had bigger problems at the moment.
Yes, we saved Circle of Magi to get templars or mages, but we learned that darkspawn are not the only threat to Thedas.
What we learn at DAI quests? That Corypheus is everywhere. He commands demons, he commands mages or templars, he commands venatori dudes, he whispers to the Wardens, he corrupts Orlais, he corrupts Ferelden, and Nevarra, and Tevinter, and Fade, and birds, and cookies, and red colour.
In DAI, the world is not bigger than the main antagonist and everything in the world is about allmighty evildoer. That's why I called DAI flat.