Each phase of knowledge has occurred with a sacrice.....Boone (first hatch), Echo (the second), Mikail (barracks)....Locke has hidden a great deal of what is behind his motivations.
Probably, this has to do with the story broadening (becoming too broad), but Locke is due one heck of an island flashback to fill in the pieces.
Locke's recent behavior after seeing daddy and ditching Kate can be construed many ways.... He made a strong case for Kate, thus implying that the Other's will need assets where they are going. Then they told Locke what she had done and he drops the notion immediately. This would imply that honesty, teamwork, and virtue are important to the experience or task at hand.
This combination of reliability and virtue can only mean that the Others are heading towards the magic box.
Obviously, there is some unpredictability to the "magic box" and, hence, the others were surprised by what came out of it. This surprise may have arisen from Locke being in no proximity to the box, yet his mind yielded Mr. Cooper.
The act of everyone heading out, while the losties + Juliet are drugged, suggests that the method of reaching the magic box is simple, incredible, or both. The group may have said a few om's and poofed away or they may have decended into holes (as almost did Locke in season one). No tracks, no trace. The island just swallowed them up.
Locke is hyper-religious, but he's not a nutcase. I don't believe that Locke destroyed the sub just to keep him away from Daddy; this is simply what Ben inferred from getting to know Cooper. Locke is now in such communion with the island that his reunion with his father is just a blip on the screen. He has put the past behind him and that is why he is being invited to discover the soul of the island.
Locke's coldness and dismissal of Kate can only mean that he is aware of the dangers of allowing the powers of the magic box to be enjoyed by dangerous people. This suggests a proximity effect....the closer you are to the magic box/the monster/the island....the greater is it's effect. So, he ditches Kate like leftover spagetti. Waa Laa!
How will they portray the center, the soul, of the island? Good question.....and probably an active topic among our very busy producers/writers. It can't be inside a building, too scientific, or too ordinary. They're probably going to Gilligan's Island the thing and put it near a volcano. Lot of drama with that approach. The island is angry!!!
OK, I'm getting off topic. But, Locke's actions are logical with the above assumptions. Ergo, the assumptions must be true or Mr. Clean must be illogical (thus making logical conclusions from incorrect assumptions).
Enough. Talks amongst yourselves....