Seems like Castillo is lined up to fight Cotto after Corrales. If Castillo beat Cotto then I certainly would think that a fight with Hatton would be compettitve and entertaining, I just don't see Corrales troubling Hatton due to his size disadvantage, and he wom't have the power to keep Hatton at bay.
IMO Hatton should fight the rematch with Collazo, he shouldn't leave it as it is, then possibly the winner of Castillo/Cotto, fighting Corrales would be a kop out IMO.