It's WAY too early for another blight when the fifth one just ended a mere decade ago
While I do agree on the one hand - it might change the situation, if another blight really were to happen:
1. All nations (with the exception of Tevinter and the Qunari) suffered from the mage rebellion and the templars no longer being the "dogs" of the chantry (so they are weakened)
2. Orlais as - probably - the strongest nation (again with the exception of Tevinter (and the Qunari, as much as I hate them), as they are not afraid to use blood-magic, sacrifices and slave-labour in order to make up any differences other nations might have (like a strength in numbers for example)) has had a civil war, too (so it's even more weakened...hell a blight hitting it might cause the empire to crumble (!))
3. Ferelden was directly hit by the blight (and lost the bulk of it's forces as well!)
4. The Freemarches were more directly hit by the mage rebellion and the corruption within the templar order (Meredith and other Templars using the rite of tranquility without proper cause and authorization!), so they are even more weakened than the rest
Hell - looking at that, we might have to strike a deal with the Qunari and Tevinter (if they would even want to help - the Qunari think all non-believers must convert or die and Tevinter doesn't like the other nations because of their chantry and what it does to mages and because they don't have slavery...), in order ot avoid total annihilation (of all nations/people - even the dalish (all of them) would have no choice but to join up...the only ones being "happy" about a blight might be the dwarfs...after all: the deep roads are nearly empty with the darkspawn crawling around on the surface...but they would need to help, too - because if the surface falls, they are next!)
=> The situation would be more desperate than DAO ever was (at least there you could hope someone else would stop the blight, if you and Alistair (or Loghain...) would fall in battle...as most other nations were still at peace, the circles still existed (as much as I hate them!) to provide mages for armies, the grey wardens elsewhere could help, the templars would be still there etc.)
Might be interesting...problem is:
You might not want to use up all of the old gods (there are only a limited number as far as I know)...
greetings LAX