"with steroline it’s about breaking down barriers... of humanity, it’s about reveling in the depravity of their vampirism" - but they're both so controlled, they repressed every bad impulse they have, they're both always so in control of their vampire urges so why would Caroline of all people be that for Stefan? And also, as you said, he already did that in the 20s with Rebekah and klaus. I feel like when SC got together there was nothing new they could do because Stefan had already done it all
Well Caroline wasn’t that for Stefan, he was that for her, he’s the one who keeps telling her to let go and if the show actually explored that it was meant to be a punishment, that Stefan was pushing her to revel in her vampirism as a way to make the crawl back to humanity more difficult and to plague her with guilt as retribution for forcing him to turn it off then it would make sense. That was Stefan’s reasoning anyway but we don’t explore that at all.