@morris:
Was it just that?
I know Uriel fights one soul at a time too, but what would it have done to the Council? Harry murdered as he stood up for what was right - and even Morgan seems to know it. Morgan who swore to protect Harry. Would even Morgan be able to stand straight when his duties conflict and justice argues against his greater duty? Or would he crack and shatter, before or after Harry's death?
Harry wasn't yet the hero of the young Wardens of Turn Coat/Changes, but he was no doubt close.
And then Ebenezar and his gang are dead if Uriel/TWG doesn't send Michael.
In other words - the deadliest Warden is internally shattered, two more of the scariest wizards in a fight (Eb and Harry) lie dead, and the Wardens who need Morgan's clarity to prevent them doing anything foolish want to avenge Harry. That is 'The White Council is gone' levels of bad.
Saving Harry's soul was the point - but saving the soul of the White Council was, too, even if it was a less roaring success.