Who is going to replace Jacob as the carer for the Island??? My answer: John Locke....
How could it be John you ask? John is dead and his name has been scratched off the list you say???
Firstly two things:
I think John is still the key to saving the island from Smokey. He was always the best man to do so - he cared for the Island and realised it was special. Secondly, it was Smokey that scrubbed his name of the list in the cave (not Jacob) and that might have been a wrong/premature move. Let me explain why...
Well, in the latest episode, Jacob asks Hurley to take Jack to the Lighthouse to help 'someone' find their way to the Island. Hurley is told to turn the dial to 108 degrees (the name Wallace-which is already scratched out). I believe that '108' and 'Wallace' has no bearing to who is coming to the Island, this was just a ploy by Jacob as he knew that this (turning to 108) would skip over the numbers (Ford & Kwon) where the images would appear in the reflection for Jack to see. Jack then turns to his own number (23). Jack smashes the lighhouse after seeing his childhood house in the mirror's reflection, although Jacob does not seem concerned by this. He (Jacob) explains to Hurley that Jack needed to see it because he has something 'important' to do but can not be told what it is, he needs to discover it for himself. What is the 'important' thing Jack has to do??? I believe he has to bring John Locke back to the Island from the sideways timeline (maybe he needs to bring all the! losties back). We are seeing snippets of what seems to be conflicting memories with our Losties in the sideways world. The blood on Jacks neck and his reaction to Desmond on the plane, his appendix scar, Clair calling her baby Aaron etc. It seems this alternate world is either trying to course correct, or memories from the two timelines are becoming intermingled with each other. I believe this is where Jack's 'important' task lies. I think Island Jack will somehow connect mentally with sideways Jack, allowing him to remember in the sideways world and realise his task in bringing John back to the Island. I believe John will soon call sideways Jack for that free consult offered to him and this is where Jack will have his chance. It's that reversed mirror image thing (symbolised by Jack staring at his refelction in the water at the temple and in the mirrors of the lighthouse), remember when it was John's task to bring Jack (and other Losties) back to the Island? Now the scena! rio is mirrored and it is now Jack's turn to do so. We know th! at the L osties have all been brought to the Island for a reason and we've heard about purpose/destiny etc. Jack is about to realise this purpose, as he is the one who is destined to bring John back from the sideways world to ultimately save the Island (from Smokey).
But thats just my theory....only time will tell.