Okay, sooo,,, Hugley and Miles are both able to communicate with the dead... or can they ???
As far as i can tell from the series so far, when a person dies, their soul, memories, personality are stored in the island's memory, if you will lol (Smoke Monster acting differently towards various characters because dead characters feel for tthem... EG Eko with the smoke monster(and yemi) )
So, my theory is that Miles can hear dead, because he is simply listening to the memories and personality that have been "stored" in to the island. Why he has this power in the first place ??????? Probably the incident, who knows...
Meanwhile, the finale shows that dead people cant come back to life (assumingly) and that someone else is just impersonating Locke, who was really dead all along. Assuming that this is true, we can assume that all the other dead characters we have seen since... Christian, Yemi, Boone, Ana, Libby, Charlie (the list goes on). We can simply assume that all these characters were impersonated by someone too, most likely the same person impersonating Locke... we'll call him esau for the sake of simplicity.
So, Basically, my theory is that "Esau" has been tricking Hurley into thinkinng he is special, he has a purpose, et cetera (which isnt to say he DOESNT have a purpose, but u get the whole manipulation thing, seeing as Esau has done it to several other characters so far, locke, richard, ben)
In conclusion... Miles can simply hear the thoughts of the island's recently deceased, because they have been "Stored", but they cannot communicate to Miles themselves. Miles can simply just hear a dead man's thoughts. whilst on the other hand, Hurley can only communicate with Esau, who is simply tricking him, or manipulating, whatever you want to belivee.
this brings up a larger question, if Esau can do all this, how ? Maybe this means that Hurley will be able to do it some time later on in the series... Maybe Miles will ? Who knows. That's the wonder of Lost lol
Tell me what you think