So we learn that Lich King is the guardian of the rifts between two worlds and without him, the sky is basically shattered and the barrier between worlds of life and death is shattered. So, before Kil'jaeden created the Lich King and threw him into Azeroth, there was no barrier between life and death,r ight? So The War of the Ancients looked completely different, with Val'kyr, etc. And why there are no mentions in ingame books about The Happening - like "A meteor just crashed in Northrend and now everything looks completely different! People that died just vanished! Sky looks strange, it's not shattered anymore!"
Or did they just retcon Lich King whatsoever and Ner'zhul never existed and Lich King was always a being of the Shadowlands?