First off, Arthas was never resurrected at all.
Second, going into a story where it is an apocalyptic phase where they hinge on the fact that "anyone can become a blasphemy" or raising the stakes so high to stop doomsday -- and yet these stakes never really matter as they dont affect the story nor the main cast or secondary cast of characters. We have had multiple fake out deaths over expansions and this idea of being pushed the absolute limit to save the world. On top of this, we know that this is the end of the main Scion story with Zodiark/Hydalyn -- this is prime time when you do this to focus the story around core characters and create new ones moving forward.
Saying "whatabout WoW" when this is the hyped end of the current saga where this stuff usually happens, goes to show the lack of stakes in play. WoW has the magnanimous problem of going from one doomsday story to the next where there are literally no stakes because the failure outcome is "everyone dies lol" after the 8th version of it..
