My theory is that the island is a nexus, for some reason. The reason is, most likely, supernatural...but the writers have been very careful to alude to the supernatural, rather than make it established fact. At some point, they're going to have to explain certain mysteries (of which the beast and Ethan are the most profound) in definitive terms...but I don't think we're there yet. I also think that there are several 'mysteries' at work, and the problem is that you can't make a universal theory to explain them all, because they aren't all together. For example: there are clear signs that things have been happening on the island for longer than many of the people there have been alive. The question is: how long? I sincerely doubt the Blackrock is directly related to the organization DHARMA, for example.
I suspect there are some events that occured because of other events, some of which occured in complete ignorance of the other. Since most of the potentially supernatural events have occured in situations where they could be reasoned away (at times of exhaustion and extreme emotional distress), we don't know the metaphysics of the show yet.
I expect that those folks who aren't happy with the show's pace will be the first ones to walk away when they get their answers. From what has been mentioned by the producers and actors, answers are forthcoming. They apparently recognized that they hadn't reveled a lot last year, and they claim they'll rectify that to some degree early this season.
Personally, I really liked this episode. Except for the fact that I think that Michael is being a real ass, in any case.