Instead of Luke drowning....
You know if Sarah had drowned instead of Luke, and Jane died trying to save Sarah it would have been a lot better. Jane's character would have shown change, and that she was willing to put someone else's life ahead of her own, and Luke could have genuine animosity for Kenny blaming him for it all, and for the way he treated Jane. It would have been a really explosive ending, and had more of an impact. Instead of Kenny holding the knife on Jane, it should have been Luke holding the knife on Kenny, and screaming about how he's responsible for Sarah's death, and Jane's. It would have been much more believable than Jane hiding the baby. I think it would have also changed Luke's character to a more hardened, and interesting person if he made it to season 3.