Q:
The "There must always be a Lich King" mantra seemed awfully suspicious, coming from ghosts trapped in Frostmourne. Was there something else going on there?A: To save people from generating elaborate conspiracy theories, we'll be serious for a moment and say, definitively, no. The ghosts of Uther and Terenas understood that the Scourge would run rampant without someone to keep them in check. Yes, that does also mean that Arthas and Ner'zhul were not unleashing the full force of the Scourge during their respective reigns: you are welcome to speculate on the reasons for that.
Q: What is the Argent Crusade's relationship with the Forsaken, in light of Sylvanas's recent actions?
A: Although the members of the Argent Crusade still stand by the Forsaken heroes who joined them in the battle against the Scourge, Sylvanas's actions since the slaying of Arthas have deeply concerned the crusaders.
They, along with certain members of the Ebon Blade, are now watching Sylvanas and the Forsaken very closely, as similarities between her and the Lich King are increasing in number by the day.