Desmond = Walt?
Walt is special. He can be where he’s not supposed to be. He makes birds get confused and crash into buildings (related to earth’s magnetic field). Walt got big. Walt lives with gramma and doesn’t look like he’s going to the concert tonight.
Desmond is special. He can be where he’s not supposed to be. He’s impervious to electromagnetic stuff. He’s running around Sidewaysville trying to gather up all the important Losties, except Walt.
Could it be that as Walt got bigger his future role to play got smaller and his pivotal place in the show was replaced with Desmond?
OR … Vincent will bring him to the island just in time (that’s who the kid loved, right?)