It's possible to be successful in the early November slot, but it's pretty much dooming your movie to a one month run, because it will die post-Thanksgiving. If you take the Thanksgiving slot, you get the bonus from the immediate holiday, and even with the post-holiday drop, there's probably enough juice to get you INTO the Christmas boost, even if you don't expect to perform on the level of Frozen. (Which would be a dumb assumption to make for any film, at least until it happens.)
I get that studios keep wanting to dodge the behemoth that takes the pre-Thanksgiving slot. Disney apparently got gunshy when Bolt went up against the first Twilight and wasn't able to break out. But they've seen three surprising successes in the Thanksgiving slot (Enchanted, Tangled, and Frozen). The studio has clout and they might as well take the best advantage of it.
I think that Thor 2 and WiR did okay. It's just that with the size of their openings, it's readily apparent that their legs were not up to snuff. And even the PIxar successes like MI and The Incredibles had strong openings but less than stellar legs. The aforementioned mid-November behemoth is more likely to hurt the early November film than the one opening over Thanksgiving.
Rise of the Guardians, for all that it disappointed in the final, did pretty well over Christmas relative to its opening.