All of Caroline’s most salient traits — her perfectionism, her type-A personality, her organizational skills — helped her cope with a diet of blood bags. She rarely loses control and seems to have gained confidence, maturity, and a wider view of the world along with her fangs.
Can you really see her going back to being human? It’s not like she wants to. In Season 4, Episode 14, “Down the Rabbit Hole,” Klaus (Joseph Morgan) asks Caroline if she’d take the cure, given the chance. When she doesn’t answer, he says, “You wouldn’t, would you? You prefer who you are now to the girl you once were. You like being strong, ageless, fearless.”
Someone will take the cure in the Season 4 finale. As far as who will become human, it’s all up in the air at this point. If by some crazy chance the blond vamp did end up ingesting it, things would be pretty different for her.
For one thing, it would mean she wouldn’t have forever to wait around for Tyler (Michael Trevino). With Klaus heading off to New Orleans, though, the younger hybrid could sneak back into Mystic Falls. Of course, their “hot hybrid sex” would have to cool down a little, so she doesn’t get hurt.
Candice Accola has said that if Caroline had never become a vampire, she would’ve stayed in Mystic Falls and spent her life reminiscing about high school. If her supernatural status is stripped away, we imagine it’s too late to put the genie back in the bottle. She’ll still go off to college, yearn to see the world, and stand up for herself.