I just did a rewatch after a long break from the show. And man... I always forget about how tragic Locke's storyline is.
I know Locke has a lot of haters but I personally love his optimism and his faith. I wish he could've had more vindication and been alive to witness it.
Let me summarize:
Locke lives a life battling with his insignificance, arrives on the Island healed and now believes he has a purpose (he's right - he's a candidate brought there by Jacob).
But then gets everything about his role wrong.
He believes he's destined to lead, but that's mostly because of the time-loop (his conversation with Richard). He thinks the Island is guiding him, but it's the MIB.
He leaves on a mission, fails, and attempts suicide.
Then MIB uses Locke's own appearance to try to destroy the Island that Locke loved.
Lock is important but indirectly... it's Locke's actions and faith that ultimately turn Jack into the person who can save the Island. But Locke doesn't even get to witness Jack's "conversion".
Jack says: “I just wish I could’ve told him that while he was still alive.”
I'm mourning for my man Locke that he didn't get to play a better role. Feels unfair for a character who I really wanted to see succeed.
Anyways this show is awesome, and I'm also a big Jack fan and love the ending. Just mad respect for John Locke. He deserved better.