I like to keep my theories brief and to the point, so here it goes:
While the island was shifting like the proverbial record, Lock was transported right after he had been shot. Sitting there alone, he was rescued by Richard who treated his wounds. By saving Locke at Flocke's request, Locke was put on a path that would lead him to turning the wheel and eventually returning to the Island. Flocke, in essence, started the chain of events himself.
Why would he do that?
If we assume that MIB/Flocke/Smoky are one and the same - even taking into account those theories that say there are multiple smoke monsters - then we can establish a pattern of behavior. MIB likes to take different guises and influence others. Unfortunatly, when he takes the appearance of someone who has no business on the island, it tends to just illicit fear. It was effective on 10 year old Ben, but not so much on other people. To pull off 'is 'ittle sceme, MIB needed to appear as Locke and create the context by which people actually thought he was Locke. As Locke incarnate, MIB was able to get his hands dirty and pull off some overt manipulation. Thusly, he was able to kill the Great Jacob.
We now have an MO.
Let me spin a little tale about Christina Shepard that blends a little fact and a lot of specualtion. Christian has some prior connection to the island. There have been enough hints and tips to make that a fair assumption. Christian is a boozer. Christian also has a daughter in Australia of all places. How did he come by a smoking hot daughter down under? We don't know. But if Christian was convinced by MIB that he needed to die to get back to the island, wouldn't that give a man a reason to drink? So much so that he lost his job? It is only natural for one facing death to push those around him away. So he alienates his son, and boards a plane to say goodbye to his only daughter. While there, he boozes it up like no other, fails to say goodbye to his daughter, and in all likelihood kills himself. Let's assume MIB posseses the omniscience to know what would happen, just as Jacob appears to. He put events into motion that would get Jack and Christian's casket on t! he plane. Now, MIB has a brand new maniupation suit all shined up to f with his son's head. The suit also worked for a date with John Locke in the donkey wheel room as well as numerous appearances in the ever-so-creepy shack.
So what does this amount to? Given that everything written above is true, or more precisely true enough, we have MIB painted as a master manipulator who lacks the charm and sophistication of Jacob. Rather, MIB manipulates through outright lies, deceit, fear, and apprehension. Look at the guilt and fear he has instilled in Jack by just a few brief appearances as Christian. In sum, MIB manipulated Locke and Christian the same way for the same purpose, namely, to get them back to the island and allow MIB to assume their personas and set into motion the events that led to Ben stabbing Jacob.