Perhaps MiB isn't "stuck" by Darkhunt

Note: This idea has already been posted by mikemac. However, this is my own longer theory and my evidence is that I posted it a day before him on spoilertv (you can find it here http://forum.spoilertv.co.uk/viewtopic.php?f=17&t=16510) and yet it didn't receive any attention. Because mine is notably longer and touches upon a few more issues, including the fact that mikemac's got more attention by using this method, I'll be reposting my version here in the theory section.

So here it is:

We heard Ilana say in the last episode that Man in Black is "stuck" in the form of John Locke. This line would hold water for me if it wasn't indicated to us in earlier episodes that the "Monster" is a shapeshifter that can take the form of things, people or corpses that it has scanned. Due to obvious inconsistencies such as Ben's judgement wherin MiB takes the form of Alex, people have either pinned it down that there is more than one Smoke Entity working with The Man in Black or that MiB's inability to change forms is a consequence of Jacob's death.

Now many people will say this is a solid explanation as to why MiB is being played by Terry O'Quinn for the rest of this season, but personally I'm not buying it. The introduction of the episode showed The Smoke Monster hovering around the island and then transforming into Flocke, and whilst subsequently it could be said that Flocke's ability to change his physical appearance and into the ethereal smoke form are two seperate things, isn't it a bit proposterous? So he CAN change his form, but he's stuck between two gears: John Locke and Smokey? I'm not so sure.

So people have put it down to the fact that Jacob is dead, correct? Well, let's alter this a bit... what if, persay, it wasn't Jacob's death but KILLING Jacob that nullifies The Man in Black's power? Breaking "The Rules"? Hence finding the "loophole"? I mean, it's a bit strange, isn't it? That we can assume The Man in Black's abilities being tied to Jacob are what stripped him of this critical ability, and yet we haven't seen anything happen to Richard Alpert in terms of aging.

So I propose this:

The line is a red herring. Ilana has been misinformed by Ben telling her that "after turning into a pillar of black smoke", back into Locke, he "kicked Jacob into the fire". Illana now thinks that The Man in Black himself is responsible for killing Jacob, meaning that thanks to breaking "the rules" he's locked in the form of John Locke when in actuality he isn't. This will be used to The Man in Black's advantage, and very well the next time we see some characters appear in places they aren't suppposed to be, they could in fact be Smokey, and this small detail that was overlooked will be used to deceive the audience further down the line.

As for why MiB is still using John Locke's form? Well he's manipulated John all his life and it's the most effective form to take in terms of consistently appearing as anyone, so it's easier to deduce why MiB would continue using the form even if some of his greater enemies know the John Locke walking around on the island isn't real.