All right so a few thoughts on Ragnarok. First I'll try to address some of Howstar's questions and then I'll present a few thoughts and questions on the nature of Ragnarok.
So Howl, you're confused about how knowing about Ragnarok would effect the Gods and how some might try to change the course of it and others work towards it. Well, first off, they're given bits and pieces. They don't know all the details of the when and such so it could essentially happen at any time (some even claim it already has happened but more on that later) so that frees things up a bit. I also don't believe the explanation that some give of the Gods trying to circumvent or thwart their eventual end. You mentioned Thor and his antagonism with Jormundgandr specifically so let's look at that for an example. Thor may or may not know the details of the Ragnorok as Odinn does since the prophetess in the Voluspa was speaking to Odinn specifically and he may not have shared that knowledge. This actually makes a lot of sense to me because if the Gods in general knew about it and/or were trying to circumvent it, why would they keep doing things that weaken them for the fight, like Freyr giving away his sword so he has to fight with a stag horn. But getting back to Thor, even if he did know, he may not have cared. Through my both my study of the lore and my personal interactions with him, I've found Thor to be a more in the moment type. I think he dislikes Jormundgandr because the serpent is large, dangerous, destructive, and unbound. This makes him one of the dangerous things that it is Thor's job to destroy in order to protect the world.
Now for some thoughts on Odinn in all of this. The Allfather is a pragmatic sort. He does what is necessary for the greater gain, regardless of the price to himself (sacrificing himself to himself to gain the runes, trading his eye for the wisdom of Mimir's well), so why would he try to avert the Ragnarok? Only to prevent his own death? Bah! He is not such a coward. Eventually all things must change and without destruction then nothing new can ever come to be.
For some thoughts on Loki's part in all this, see
this linkthis link which I have posed before in the thread on Himself.
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Now to address the Ragnarok itself. I mean just what is it even? Well first let's all remember that the tale doesn't end with the deaths of the Gods and their opponents. Not all life is destroyed and not all the Gods die. Some are even reborn. Many of the Gods have children who step into their roles after the battle and Balder is released from Hel's realm to take his father's throne. (
Actually all the inhabitants of Hel are loosed and no one ever mentions where they get to, or what happens to all the battle slain the Odinn brings to the fight. I mean, they're already dead so are they reborn after the battle or do they go to some higher level of afterlife? And just where does a dead God go?) And of course the man and the woman who were hiding in the branches of the world tree come down to rebuild the world from the mortal end of things.
Now some folks claim that the Ragnarok has already happens and will happen again, that it is a cycle of destruction and renewal and as the new generation of Gods claim their fathers' places, they essentially become them.
Some claim that it has already happened in a more metaphorical manner; that the deaths of the Gods and the survival of humans, hidden through the destruction, only to re-emerge when the time was right represents the destruction of Heathenry (and paleopaganism in general) by Christianity and the re-emergence of the Gods and the old ways into the modern world. Just enough of a seed left to build on.
Some believe it is entirely literal and yet to come, some that it's only a possibility or that the Volva was lying. Still others say that the story is too mangled by time and the writer's revisionism to pick the actual heathen beliefs about the end of the world (if any such existed) out of what remains.