The blood pouring on the floor was the key. She will bring him back ala Beric. she still has the hots for Jon Snow. What's going to be interesting is what the Wildings will do to the traitors who killed their ally. Don't get the Giant pissed you Night's Watch traitors. That scene reminded me of the death of Julius Caesar.
Also, were those horsemen, the Khal's army? They probably will rally to Khalisi when they see Drogan. An army of lethal horsemen and the Unsullied as foot soldiers along with 3 dragons will be formidable especially being advised by the Imp.
So who kills off Bolton and company? Littlefinger and his Knights of the Airee? He is the wild card in all of this, huh? When the Mountain kills off the holy rollers for Cersei, it'll be a very pissed off Cercei and her brother wanting big time revenge on the Sand Snakes and their bitch leader for killing their daughter. The Lannisters always pay the debts. Brohn becomes Golden Hands first knight and they lead the Lannister army to punish Dorne and then pay Bolton a visit next.