A switch in perspective on the Dalish is dependant on how related they'll be with Solas' plot. But on a generale not I think it'd be best to not expect a overall good situation or portrayals for the elves during and post-Solas' plot. They're going with the plot of having them as the next antagonists, at least Some of them. Maybe the can go with the Dalish being against him?
I don't think there'd be any "switch to the Dalish perspective" - the closest to that would be Dalish Inquisitor I guess (if they show up and have any significant role), but that's about it. The Dalish are merely a splinter group of a bigger whole, so I don't see why they'd become a focus, over elves overall. Even the last epilogue slide makes it clear that ALL elves of the south disappear somewhere, not just Dalish (whom most Southerners wouldn't notice the disappearance of).
Plus, I don't really see how they'd be related to Solas plot any more than others. In fact, with their dedication to Evanuris - who so far as established as pretty bad individuals - I have to wonder whether some Dalish would fight on their side, provided they'd ever be shown as an active force in the universe. It IS a distinct possibility.
Though even if that scenario materializes, I don't think the story would focus much on it. e're getting to a point where the story is bigger than any specific group - which includes humans. We'd definitely hear more of ancient elves, as well as groups of elves we haven't yet hear much of before (like that red-vallaslined hostile elves from Tirashan).
It's the same for wanting Solas' story to have an happy ending. To change that it'd require a change on the main plot related to him, which I think it's unlikely, regardless if he accomplishes his plans or not.
It's not about Kirby's views (on that note I disagree with Xil. I want her in DA) or Weekes. It's about a general view and plot of the team that started at least with DA2, which continued in DAI and will continue, almost surely, in the next game. It'd be best to prepared.
I don't really see how "wanting for Solas' story to have a happy ending" somehow would require them to rewrite the main plot
Realistically we have no idea where the story is going, nor what could even be considered a "happy ending" either for the world or characters - unless we're talking some kind of specific, sappy 'happy ending' from Disney movie or something?