I have an idea pertaining to the Smoke Monster as a character I'd like to see what you guys think about. This post puts for a lot of ideas and I'm sorry if it rambles a bit but stay with me.
So we know now that the seeming source of the Monster was the Light. Mother described the Light as a balance of all the forces in the world, including death, birth, rebirth, etc. She also seemed to describe it as a Source of Power, something that Mankind could harness and do both wonderful and terrible things with. She herself seems to be able to tap into it, and perhaps whatever ritual she performed with Jacob allowed him to tap into it as well.
So Jacob in his fit of anger knocks out his brother, MiB, and sends him into the Light. Moments later, the Smoke Monster appears and rampages off into the jungle. I believe that whosoever can somehow tap into the Light, or enter into it, can become a powerful, near-godlike being, having been possessed of control over Life, Death, Rebirth, etc... in other words, Jacob's brother left his mortal body and was "Reborn" as the Smoke Monster, just as Jacob through Mother's ritual has become someone we know can give a man the ability to never age.
Here is where Smokey as a character enters the equation. I believe that the MiB we saw before entering the Light is mostly gone: the entity that emerged is a personification of the emotions raging within Jacob's brother before he entered the Light. However, the entity (Smokey) is heavily weighted onto the "Dark" end of the spectrum. I hate to use the Force from Star Wars as an example, but remember how Annakin Skywalker was supposed to bring balance to the Force? Well, he got corrupted and heavily influenced by Evil for quite some time--after his defeat at the hands of Obi Wan he was reborn as Darth Vader, and the Force became imbalanced and Evil spread throughout the galaxy. At the end, however, influenced by the peril his son Luke was in at the time, the compassion and love within him finally reemerged, and he regained his humanity.
I think that it was extremely obvious from this episode that Jacob's brother (the man) was far from evil. He was angry, certainly, and perhaps envious and judgmental, but all of these are human emotions. However, since he entered the Light in a state of extreme anger, anxiety, resentment... the entity he was reborn as reflects all these traits.
Finally getting to my main point, I believe the man, capable of love and compassion, is still there under the surface. What if each time Smokey consumes the memories of a person, he regains some form of humanity? He has already shown some bleed-through from original Locke ("Don't tell me what I can't do!") and he seems to be possessed by curiosity, and the urge to leave the Island, much like Jacob's brother was. I believe had he left as a man, nothing would have happened at all. However, now, being the Monster he is, leaving would unleash him upon the world, and thus Jacob has to not only protect the Light from the outside world, but also the outside world from the Light... or in this case, the Dark (Smokey).
My idea is that after years of consuming memories, Smokey is no longer a blind raging force of destruction, but is close to finally regaining some form of humanity and returning balance to the Force... er, Light. What if the Candidate's role in all this is to merge with Smokey and finally bring the balance back to the middle, much like the scale with the light and dark stones balancing each other out? The being formed from such a unity would sort of be like the Jacob we've come to know combined with MiB... not a distant, gentle but naive god like Jacob, nor a raging and destructive chaotic god like MiB, but simply a powerful being that was in the middle of these extremes? Or even, a being that would simply merge back into the Light that spawned it?
What do you think?