If they decide to make the series a statement on immorality / crime doesn't pay, Walt will end up in prison, solitary confinment, disgraced, dying of cancer, his thoughts haunting him till the day he dies.
His wife and children, the reason for him starting his life of crime, all destitute or dead.
Hank will be the one to take him down. Marie will be crazy or dead or in jail before this is over.
also some puppies will be born