You two, stahhpp it.
You're killing me with diabetes.
Ah, but that's what we're here for.

I think the hypothetical Cure will come into play when we explore Weisshaupt. Inquisition has been alluding to the idea that there's a civil war going on there. Why that is remains the question, but we'll certainly see the Wardens as an organization go through change when we do explore the conflict.
Considering the Cure and
I'd say the Wardens will come through whatever is going on as a better organization, and will be ready when the next Blight comes. Considering Inquisition's focus on "leading an organization", perhaps we'll have some part in that aswell. 
I can see something like that happening too; something like, the Warden returns with the cure, and it ends up driving an even bigger rift between the two Warden factions than there already is. Southern Wardens are all over that, are now all Calling-free, while the more staunch traditionalists up north oppose it vehemently. Could be interesting.
What do you guys think about playing as the Warden again? Yay or nay? 
For a whole game? Nay.
For a DLC/expansion revolving around their search for the cure? Definite yay. That right there is too big to leave to headcanon.
After that's done, though, I kinda hope they leave the Warden and Leliana alone.