I think that we'll see the first wave of the Battle at Castle Black. When Jon returns, and the attack occurs from South of the Wall from the Wildlings who climbed the Wall with Jon. And, we will see Ygritte's death. And, the final shot for Jon's arc this season will be him atop of the Wall looking down at the massive army North of the Wall. Then Season 4 (or, at least the first half) can focus on the proper Battle at Castle Black!
