On
his website he says that Feast for Crows was too long. Instead of splitting it into two parts, he split it into two seperate books.
"The focus in FEAST will be on Westeros, King's Landing, the riverlands, Dorne, and the Iron Islands...Meanwhile, all the characters and stories removed from FEAST are moving right into A DANCE WITH DRAGONS, which will focus on events in the east and north"
So, awesome that this one is coming out, sad that there's more I'll have to wait to read.