This is a fairly complex question, it really deserves four separate questions. Thus, I will give you an answer, but it will be brief:
Pro-exile: Montag could be rid of Mildred and the unthinking life that began to wear him down.
Con-exile: He no longer had a home and could not show his face in society again.
Pro-exile: Odysseus had the opportunity to learn to better trust the gods and obey. He learned that responsibility earned their favor and his blessings.
Pro-home: His obstacles subsided.
Con-home: The suitors awaited him.
Con-exile: He was separated from his wife, child, and family.
THE ADVENTURES OF HUCKLEBERRY FINN
Pro-exile: Pap couldn't get him. No one could civilize him.
Con-exile: He didn't have appropriate child-rearing.
Pro-home: Huck had cash, a nice bed, and the chance to spite Pap by going to school.
OF MICE AND MEN
Pro-exile: Lennie could not hurt anyone but himself.
Con-exile: Lennie could likely not survive alone on his own.
Pro-home: People would help Lennie.
Con-home: Lennie would always run into trouble by touching soft things.