Most of the Nordic legends happened between 3th and 8th centuries AD. Kratos lived in golden age of Greek Mythology, roughly 1300 BC - 700 BC. If Kratos isn't an immortal lived over thousand years, then yeah, they are ditching him.
I dunno, Kratos has crawled out of Hades in virtually every game. What's another turn on the spinning blade-go-round to a guy like him!