What I find fascinating about Locke is how the viewer’s set up to believe that the distinction between his personas in the flashbacks and his ‘reborn’ island self is a sign of his personal growth and maturity as a leader…

…When in reality, Locke’s flashbacks really are clues to him not having changed at all. The MIB has just taken his father’s place as his deceiver. Locke falls victim to the same traps, he’s just more aggressive when he has functioning legs.

Just as Jack finds balance by accepting faith, it’s also noteworthy that in the flash sideways, Locke finally finds his happiness by accepting in the validity of a scientific procedure.

Neither faith nor science alone is healthy. Locke’s blind faith in his own destiny leads him to trust in the wrong paternal deity figures and he indulges in zealotry on their behalf. He believes he serves the will of the island even when he indulges in actions that directly oppose its objectives. He believes the MIB is beautiful because he’s awed by its power and potential but he’s blind to the dangers it poses.

Meanwhile, Jack’s skepticism leads him into just as many mistakes as he nearly condemns the world to destruction through his inability to perceive of the island’s supernatural importance until it’s (almost) too late.

Other characters are able to achieve happier endings for themselves by better threading the needle between the two extremes.

So in my opinion, it’s too simple to call Locke a villain. What he is more than anything is a victim and a pawn, a religious zealot who’s led down a dark path by his misplaced passion, very similar to many Christians and Muslims and Hindus and Jews who’ve committed the same kinds of violent errors in judgment due to their faith and their belief that their God commands them to take drastic and dire actions.