After rewatching S-5, I came to a realization that many of you have probably already come to... the irony of Ben Linus, they guy we all felt was the most evil, turns out to be the ultimate pawn. As a child, he was Sayid's pawn. As he grew, he became Richard's pawn (Dharma genocide--etc). He was used by Eloise Hawkin to bring the Oceanic 6 back to the island. And then, just as Jacob brushes him off as a nobody, we see him being manipulated by Flocke to kill Jacob.
For 5 seasons, many feared Ben Linus. Turns out, he was blind and impotent, with no island "purpose". In fact, his desire to have a purpose was his motivation, throughout the show. Truth is, in all his flailing about, all he ever wanted was for his meaningless life to have meaning.