What world do you guys/gals think Arc 2 will take place in?

I think its Grizzleheim.

Your friendly neighborhood Orando

I'm hopeful that Arc 2 will take place in more than one new world. But if you mean which new world will show up first in Arc 2? Then I must say it will be Polaris.
1. With the destruction of Kane & the Armada going "haywire", Valencia may have to make truce with Marleybone.
2. Mycroft Bones will be concerned now that Napoleguin is back on the throne of Polaris, he may send us on a "fact-finding" mission to Polaris. ( Unaware, of course, of our past history with Napoleguin. )
Or it could be completely unrelated to the Armada story and we could be concentrating on our mother's diary/ies ( KI writers used both terms in our Presidio companion's promotion, I wish I knew whether we have one diary or more belonging to our mother. )

I REALLY hope we go to Darkmoor next, fighting all sorts of enemies, plus we may get to see more of Bat Masterson's kind, maybe even fight a few of them, because it's one world that has only ever gotten a glimpse of, or maybe a few of those strange, unnamed worlds seen through the passage between stormgates, like that dark lighthouse world, but i would love if we got a special Darkmoor exclusive companion for the crew.