My money is still on Jane Foster as the new Thor. This preview at least confirms that it is NOT one of his granddaughters from the future.
Kind of silly to leave a book where you think the writer just had one of the best runs you've seen. Why would you think he couldn't follow it up with another "worthy" story? As was mentioned, the classic Thor will still appear and this will undoubtedly be an important chapter in his mythos as well.