uh... the entire conversation where he reveals truth and proves to Richard that he is not in fact dead and is not in fact in Hell, and that those were MiB lies?
Yep, that was the truth. But he told him that not because it was the truth but because it was the opposite of what Smokey told him. He told Ricard what he needed to to manipulate him to be on his 'side' - look no further than his 'gloating' by having Richard give the white rock to Smokey. What more of a childish 'ha ha' could you need?
Again, I'm not saying he lies ALL the time. Smokey doesn't either - he came to Claire and admitted his own lie about Aaron to her, telling her the truth about Kate taking him. He didn't do this because it was the truth, but because by telling her the truth at this point, he could further manipulate her.
I think the big answer here is that both Smokey AND Jacob are wrong - people aren't inherently good or bad. They are self serving. And both Jacob and Smokey are as well.
No. Jacob has manipulated the candidates no doubt but in the same manner as MiB? Nope, it certainly doesn't seem that way. Jacob wants people to come to their own conclusions, make up their own minds and look within themselves for what is right and wrong. MiB has no such desire. He directly leads and uses their love - Nadia, Juliet, Aaron, Isabella - as a means of control and weapons against them. And name 1 person we have seen or know of that Jacob has murdered by his own hand. We have seen no such action and there are no clues pointing towards Jacob as the killer of the Ajira folks, whereas MiB has murdered dozens. And simply from a common sense stand point, would the man that so savagely killed Eko in cold blood be a "good guy"?
We have seen Jacob manipulate people in exactly the same manner as Smokey. Case in point - Jack and Sawyer. Smokey shows Sawyer his name on the ceiling, knowing that for Sawyer this will piss him off and win him over. Jacob shows Jack his name on the wheel, knowing this will feed his need to be important, and win him over.
As to killing with his own hand - you're cutting a fine thread here. Killing through others or killing through neglect doesn't resolve you of responsibility. You mention Nadia - who stopped Sayid on that street corner, saving him but killing her? I may be mis-remembering, but it sure seems like it was Jacob. And why? Because it fit his plan - not because he cared about Sayid or Nadia.
I think it's also important that killing hasn't been Jacob's job in this little 'game'. It's Smokeys. We haven't seen people killed off by Jacob because that's not what he needs to do. Smokey kills off extras when they either don't serve the game's purpose, or when they are no longer useful.
I have no doubt it's possible that Jacob is a god-like figure and Smokey is a devil-like figure. It just seems a tad too black and white for this show - or for it to be all that interesting. It's a very pedestrian story, and one that doesn't lend itself well to hidden plots and secrets. For example, the others stories you cite - especially the Dark Tower series - there isn't any ambiguity about good and bad, and the motivation of said characters isn't ever in question. On Lost, that's not the case. The motivations and backstory of Smokey and Jacob are a key piece of the unanswered questions, and I think the answer that Jacob is a good guy trying to contain the evil that is Smokey is just too...pedestrian.
On an unrelated note...sort of...I predict that we get a big Jacob/Smokey flashback episode in the fourth to last show, with a big showdown in the 3rd and 2nd (they'll want to start the showdown just prior to the big finale to drive even bigger ratings), with the final hour wrapping up how the outcome effects all the characters and brings the timelines back together.
