During Mob of the dead the charcters are in a endless cycle,everytime they die the cycle restarts them not rembering anything,except for bits and pieces of things,which the leave behind as messages to their selves so they can break the cycle.(I belive thats correct.)
Anyway my theory is that treyarch used mob of the dead to sum up the whole zombie story line.What I mean is that once the main group,gets sent back as primis,the cycle is restarted,making everything that lead up to revelations happen again and again,but maybe treyarch is using the M.O.T.D plot to release the real ending that breaks the cycle,we may have to wait,but I think that treyarch is going to be droping little things here and there in diffrent maps that unlock the real ending.
Ok, to sum what I just said is that I belive treyarch is using M.O.T.D's plot to create a real ending for zombies, aka that they will drop little things here and there from our main characters who have already been through the cycle, making them remeber and eventally break the cycle.
Now remeber this is just a theory, so be nice.