One thing I disagree is the idealists vs nihlists comparison. I see it more as idealists vs pragmatists.The outcasts realize that helping the locals in the long run won't mean a thing.I believe,all things being equal,the outcasts want to help the locals they understand that they can't fight everyones battles for them.It is sink or swim time for humanity.If you give them food they give you a gun and tell you to point the noisy end towards the bad guy and wish you good luck but that is the extant of thier generosity.
Sorry, I didn't explain this properly. My "nihilists" are the Super Mutants, who admittedly haven't been talked about in depth. However, every mention of them seems to paint them in the light of mindless aggressors and enemies for the sake of having enemies.
But that's not entirely fair. There's no saying what role the Enclave will play (though my money would be on thme being somehow responsible for the Super Mutants, thereby reducing Fallout's two main "evil factions" into a single source of pantomime evil) and there is of course the "Outcasts" who are as you say, pragmatists. I just hope they have more depth than simply being "tomb raiders" out to loot pre-war tech.
Would this be a fair evaluation of the BoS mindset?
They're not quite that selfish, and they're not unified in their views. They're happy to fight battles they believe they can win at minimal cost, and their technology enables them to earn dominant victories against enemies beyond the means of regular wastelanders, so in some respects they are protectors.
Yet when it came to the mutant threat, they were reluctant to believe there was an army amassing, and very reluctant to commit toward any offensive action. Without the Vault Dweller's influence and persuasion, it's unlikely the BOS would have done anything but defend the Lost Hills Bunker to their grim demise. There was a certain amount of division in the BOS ranks, but probably not as much as you'd expect from the seemingly regular schisms in at least three (not necessarily released) Fallout games.
Also has there ever been a discuussion of the BoS goals past survival(I bet that one is pretty high on everyones list in the wastelands)
Such as
Become the teachers and guides for humanity when the time is right.
Become a Machiavellian power behind the throne who controls the power structure
To create a Utopian society for them and them alone
I ask because it seems they have an agenda beyond basic survival and was wondering if it has been mentioned anywhere.
I'm sure there has been at some point, but I don't remember seeing one here. It's definitely worth reading
The Vault, since it has some good summaries of what is "known" from previous games.