Breaking the bottle by Pete

We have finally seen what the island represents - a cork, a sort of Pandora's box which keeps evil from spreading. Where does this evil come from, why exactly can't it spread with the island in place, how does this island protect the world exactly is not something we really now (though we can guess it has something to do with the special energy sources upon which it rests). We also know now that moving the island does not prevent it's protecting capabilities (if Jacob had a computer, he would probably say the island is a firewall). I guess that things left unsaid regarding the island and its corkness will be answered within five or six episodes. Onto the theory:

There are not many slow-motion shots on Lost. However, the very ending of the last episode was one of them. In fact, it is the first one that I remember, and it just might be the telling sign. So, what could it mean?
It could mean that MIB found a way to render the island obsolete, much like the Alexander did with the famous knot. Namely, if MIB finds a way to spread darkness regardless of the island, it will remain in place (like a cork in a broken bottle), but without any significance. Now, we have seen the island underwater in the paraflash, so we might ask ourselves - well, the houses are still standing, the people are healthy, Jack has a boy, and dr. Linus is a cool guy - what up, Jacob? Where is all the darkness? It is looming, I would say...the merger of the two worlds could actually reveal the darkness as it actually has spread silently, sowing the seeds of an eventual destruction - not of the world as in some cataclysmic war, but of the hearts and minds of people facing critical situations in their lives. I guess that the true fall would be simply a loss of free will - giving way to one's own affections, impulses, etc. At the point when this happens, we might see a direct link b! etween how events on the island influence those of the island...
But look at this - what if something altogether opposite is the case? What if the destruction of the island is not due to MIB, but to Jacob? Sticking to the bottle break, what if the only way to prevent MIB to spread his evil is to sink the island and everything in it? One could say that this would go against the corkness. However, think about the Jacob's lightbulb moment, after which he offered Richard a job. What if he has another one of those, where he realizes that there is no point in bringing people to the island and showing they can do good because it still tampers with their free will. And, what if he realizes that the only true way for people to show what can do with the free will is to let them face the world without the cork island, the looming evil of MIB, the good touch of Jacob? And what if Jack is meant to do precisely that? Initiate the sacrifice of them all on the island in order for them off the island to have truly free lives, whereever it may lead them? A! nd as the reward for that sacrifice, everyone is granted a new life in the island-less world, where, as with the island, what happened in the past does not matter, because each of them has an opportunity to start anew. And, given that opportunity, they just might be able to make some better choices this time around (a la Ben)?
However, one might ask why would Jacob sink island, isn't he looking for a replacement? Well, since he's dead, he might want the candidate to do the sinking himself - activate the volcano and whatnot. All this sounds like a good way to achieve the ultimate redemption, to be found, if you want to interpret the title of the tv show as not only being geographical in nature, but also more spiritual (as it is by now clear that it also means that). It may sound good for an ending, but it still leaves unanswered the mystery of what is the temporal relation of the paraflash happenings and the island events, and what are the people on the island to the people off island. And no theory can be complete without plausibly explaining the two. So, consider this only a partial rant of the ending of the show, and of the MIB's plan as inferred from the very ending of the last episode.