To get off the island, which he's made abundantly clear. We've also been introduced to an entity that's more powerful than him (and, presumably, even Jacob) -- a fact that often seems to be ignored around here, which itself boggles me to no end. That entity appeared as a teenager that warned him that he was breaking the rules, and Locke was both visibly frustrated, scared and angered by its appearance.Locke is gathering strength? Okay ... but why? for what purpose?
Oh, I don't think we've forgotten about it, we just don't have enough enough to really formulate a theory about who/what it is and their motivations other than enforcing rules. So, no need to be boogled!
If you have theories, present them!
Mr Awe