That Mistakes happen is okay, but when you want to fix a mistake you should follow the right way with the players. First step communicate the Mistake and what you wanna do. The Quest runs 7 Days so its enough time to get the meanings of our players. Then find a way that is accepted from all parts of the game.
For me it should be a fine Move if Plarium reduces the Mistake about 50% then i think all are fine and it helps to revive armies or that coals grow and can fight a bit bigger.
Other Way is to max out the free revive to all armys you lost on 60-75% then the players wont get the Drachs but they get Back some Troops they sended for the Mistake done from Plarium.
I think its a bit time to fix the Problem better then in Moment and that the Players that pay the workers of Plarium also get more happy then in moment.