Her biggest dreams go unfulfilled and got overshadowed by an ignorant city elf, a cantankerous human apostate, and a Chevalier and Empress who got their jollies from keeping elves down.. or outright murdering them.
The best path for Merrill at this point is to just forget it and pay attention to the present. To help the alienage.. not look to the past. That's definitely nice. I just think it falls a little flat. She and Fenris just end up in the same place narratively. They might as well have only written one of them.
Well, on the rivalry path this is exactly what happens. If she shatters the Eluvian and decides to focus on her contemporaries, she's no longer concerned with whether or not her "biggest dream" remains unfulfilled.
Narratively speaking, I think Merrill still stands out. Fenris is off hunting slavers, but he doesn't consider elves of any stripe to be "his people" and he's not killing slavers for the sake of
elven slaves specifically... Merrill has always had a bleeding heart for the elves of the alienage, the ones in the Circles, those enslaved in Tevinter, and ofc the Dalish. I dunno. We have never had another elven companion who cares as much about them as a whole, so whether she's more focused on the past or the present I still think Merrill's place in the story is a good one.
This is all one big fat IMO, however.