@Sven:
And if the Island goes up in flames, then people will die. There's no way everyone can escape, especially the CP9. Luffy would not leave people to die like that, and there's no way Franky would leave without ascertaining that his family is okay. And so far, an arc has not been made out of a previous threat that the Strawhats have run away from. It would drag. And they have declared War on the World Goverment. Whatever you'd love to personally happen, The Strawhats are going to grow vastly in reputation. They've been playing with the big boys for a while now, now it's time they are recognized for it. And if they do fight the Buster Call here, they will be protecting people. Maybe not "Innocents", but people will die if the Straw hats don't protect them.
but everyone's leaving the island so how are they all gonna die, by the time the BC gets there, it's gonna be like a ghost town, so then we'd have Mugiwara beats BC to save everyone but no one was even there.
@Sven:
They obviously don't get on, but do you think they are at war? I don't think Shanks is the sort of guy to directly attack a goverment installation.And while we don't know enough about Newgate to say that he probably would and wouldn't do, I doubt he's attacked the goverment directly either.
i'm not saying that they directly attacked the government but what i am saying is that they're bound to have fought with several high level marine/goverment officials in their time on the grandline. and to be honest if Shanks would willingly loose an arm for kid he barely knew for a month then i doubt he'd flinch at invading any Governement installation to get back his nakama.
@Sven:
She doesn't want to beat the Buster Call, but she's scared of it. If the Strawhats don't defeat it, she'll still be scared of it. And the main theme of this arc is Robin/Usopp coming out of their shells and becoming valuable crewmembers. Defeating the Buster Call would tie up both of those things very nicely, if Usopp has a role in it's defeat. And the Buster Call isn't really that scary. It's 10 warships commanded by Five Vice-Admirals. If Oda had intended it to be the epitome of power, he wouldn't have shown Saul annihilating half of it, only to be beat by Ao Kiji. Who is the epitome of power.
And anyway, the Straw hats have shown that they aren't scared of the things that normal people fear. They beat God Enel and Crocodile.
i disagree that the arc is about bringing robin/usopp out of there shells, i would acually say the arc is about reinforcing the bonds and highlighting the importance of friendship, i personally think that the whole power up thing is just a knock on effect to show the importance of what they're fighting for.
@Sven:
But they aren't the only people there, yet they are only the ones who could probably take on the Buster Call (The CP9 could probably stand a good chance, but they are in no state to be fighting).
Other than the CP9, their enemies, the Mugiwara as of the next chapter, should be the only ones there, along with the defeated. i really see no reason why they should run back and save people they've just thought.
In addition, one of your points had undertones of joining up with Galley-La/FF, i do fear you're forgetting what Nami said, the Mugiwara do not plan to go back to EL from the Bridge of Hesitation, they plan to go forward through the Gates of Justice. What the navigator says, goes.