The blog "Be Here Now" got me thinking about spiritual advisors and leaders. So read that post then read mine. In that blog, Ber418 spoke of Richard as being the one to chose and seek out the new leader of the Others. This is true because the producers have said as much on their podcast. They also said that Richard acts as an advisor to Ben. The two of them keep the other in check and chose the replacement for the other if it becomes necessary.
So my thought is maybe Locke is supposed to be the new Richard and Jack is supposed to be the new non-evil Ben. Jack has been in a leadership role since season 1. He is sitting back now because he doesn't realize his purpose yet. This is where Locke will come in. We have already seen him try to spiritually guide Jack and has already started to succeed in getting him to have faith in the island and whatever purpose he will have.
This is all speculation especially since Locke and Jack aren't even in the same year at this point in the show. I have no concrete evidence but we have seen both characters try and act in these capacities. Locke is not an effective leader and I think he'd be a better advisor. If Jack is made leader he could replace Richard with Locke. I think it is a real possibility.