Jacob wanted/needed to be killed by Jack Thursby

This was the prevailing thought until Miles told Ben of Jacob's last thought, that he hoped he was wrong about Ben. However following last night's episode I must conclude that his plan involved dying.

When Richard went to kill Jacob, Jacob quickly attacked and disarmed him, showing he clearly has the ability to have stopped Ben should he have chosen too.

Now onto why he needs or wanted to be killed, after the initial talk with Richard he realises he needs to change his game plan for keeping the Man in Black contained, that MiB will keep trying to kill him. Before he's just been passively getting people to the island to prove a point, now like the MiB he decides to use those people. He starts over 140 years to put pieces into place for when he dies, I think the best example of this is the ability of Hurley to speak to the dead, not only so he can communicate with him, but knowing that Richard will lose faith and his wife is the only person who would be able to stop him.

Other examples may include Ben, and why compared to Dogen and Widmore who know of the candidates he seems not as knowledgble. Jacob had him kept in the dark to drive him to killing him. Knowing that he brought Miles to the island who would later tell Ben his last thoughts as another way to pull Ben back to his side. Perhaps Locke too as you can see the bleed through into Flocke, perhaps this being key somehow.

Jacob seems to have set into motion a plan 140 years ago, perhaps changing his role from merely guardian of the island, to destroying MiB. He certainly seemed to change his methods from just pulling people in and staying out of it completely, to using Richard to give people nudges.

(Sidenote: I think Hurley is sort of an antidote to MiB. As the MiB often seems to ofter people thier dead loved ones back which is a false promise (or at least he'll kill them and they'll be together, so he kind of kept his promise). Whereas Hurley can give them the real deal and help people let go, Nadia wouldn't want lots of people dying just so Sayid could have her again)