Ok, so Miles says he only is able to get dead people's last thoughts. But in his Flashback a while back, Miles tells a ghost "you can go now", in an annoyed way...kinda like a rude version of Haley Joel Osment in the The Sixth Sense, telling a ghost that they are done. To me, that's far more than just "last moments". So was Miles telling the truth? Or hiding something significant? Ken Leung has been great when he's been on screen, but the time seems sho short, and relatively insignificant. Hope to see more..
It seems they've changed his powers a bit as time went on (probably to reduce its effect and make Hurly more important). It's application as we've seen it for the most part (on the island and the flashback he had with Naomi) is very inconsistent with his very first flashback.
I think it may be both, maybe. Perhaps when he's actively trying to use his power, he really can only see the last few moments and thoughts of a person. Occasionally, however, he gets something more in a fashion he can't really control. Kind of like how Hurley can't shut his power off or even turn it on; the dead just come and go as they please.
I thought him telling the ghost to go was just his "show" in order to charge people for his sort of scam. Like pretending they were haunting the people even though they weren't.
If i remember correctly, there was no one else in the room, living anyway, when he said "you can go now" or whatever, so no need for a show. I also seem to remember when Claire kinda just dropped Aaron in the woods and ran off with Christian that Miles was "Seeing" something funky going on.
What I thought most peculiar was how he was able to hear the dead Jacob from his ashes. Recall that when he was not on the island yet, that the idea of a cremated person concerned him, and that he wasn't able to contact this guy's cremated son. I really hope we get an explanation for how he came to have these powers.
Perhaps Jacob met young Miles while he was still a baby on the island but before the Incident and imbued said powers to him?
There was a bit in "LA X" when Sawyer said that Miles was the only one he knew who could tell what someone was thinking when they died. A few scenes later, NotLocke! tells Ben what Locke was thinking when he died. Hmm.....
Remember the 80s movie Starman - where the alien being 'became' whatshername's dead husband? Well, I kinda look at it like that - except it continues to the extent that notLocke had access to everything in Locke's brain.