What I'm seeing here is a repeat of a theme... MIB is using the weaknesses and wants of the candidates (& Claire?) to recruit/manipulate them...
Sawyer: Wants to get off of the island in a VERY bad way to get rid of the place where so many bad things happened to him.
Claire: Wants nothing more than to have her baby back.
Sayid: We saw tonight that all he's ever wanted was Nadia... MIB totally used "what if you could?" to manipulate him...
I dont know if he's planning on doing this sort of thing with Jack, Kate and Hurley but I guess we'll have to wait and see