Earlier quoted context omitted.
Me too. I find it fascinating that pretty much every religion has a messiah theme. The big three of course, but also Buddhism, Hinduism, Taoism, and ancient religions like the Mayans and Persians. It's such an out there idea - that of a saviour to return to impart perfection - but so prevalent that I'd love to see a more intellectual exploration of the topic.
I am not familiar with those religions, but aren't they monotheistic? Because I don't recall Old Norse mythology as having any saviors (though the gods were supposed to fight the evils after Ragnarok).
Ragnarok is eerily close to the Armageddon story however, complete with monsters and beasts, darkness and destruction of the planet by fire from the heavens. It's also very similar to the Mayan and Hindu "rebirth following destruction" theories.
I'd posit that the "saviour" component of later religions is perhaps just a development of the darkness in the rebirth narrative.