Wouldn't be the first time the Wardens were exiled from a country. Orlais will not be safe for the wardens once it is known that they were the ones who killed the Divine and flooded the world with tears in the veil pouring demons into the world. No matter their reason for doing it, there has to be consequences for their actions at the Temple. Were they being controlled through blood magic or were they willing participants? Who really know how much influence Corypheus has over the Wardens? They are too dangerous at present to be allowed to remain.
Once Corypheus is dealt with, the Wardens can look to redeeming themselves.
Corybits is hopefully dealt with in DAI but if one darkspawn magister could almost destroy Thedas with Grey Warden help the risk the other 6 unaccounted darkspawn magisters are to Thedas and the Grey wardens should be considered maybe almost as much as the known expected threat for two more AD blights.
There might only be 2 AD left which the Grey Wardens are still needed for but equally or perhaps even more dangerous to Thedas are the 6 unaccounted for darkspawn magisters.
Either choice with the Grey Spawn has risks to the safety of Thedas. It makes the choice a great dilemma especially as offered as just a very quick post battle knee-jerk decision with very limited ability to realistically RP outside of head cannon how this important choice may impact Thedas.
Since darkspawn/blight and Grey Wardens are such I big part of Dragon Age I just wish there was more ongoing intelligent dialogue regarding the ongoing risk and benefit with in-game NPC and companions.
I love that DAI had great thought provoking choices like this one. With the significance of blight/darkspawn and Grey Wardens I would have also enjoyed seeing follow-up dialogue from at least the leaders Orlais and Ferelden especially if you exile the Grey Spawn but Bioware had a lot of story lines to juggle in DAI.
DAI had a proto-darkspawn leading a possible AD to destroy Thedas and yet there is only silence from Weisshaupt especially after the world shaking failure of the southern Grey Spawn. It would have been an extra nice game moment to continue dialogue in-game on the odd silence from Weisshaupt since we will hopefully find out in a future game why they didn't respond. It would have made an even richer world in DAI IMHO, assuming problems in Weisshaupt will be important in a future game.
Also would have been even better if Bioware let there be more than just one southern Grey Warden that was not sack full of hammers derpy enough to blindly follow a questionable plan from a too ridiculously obviously evil Vint mage. At least they had some Grey Spawn come to their senses once the Inquisition started killing them.
I'm surprised there wasn't an in-game easter egg comment how the Inquisition and Grey Spawn interaction at adamant fortress in DAI was like Sir Lancelot in Monthy Phython and the Holy Grail Red Wedding scene.