I'm more of a Sam/Dean girl and prefer exploring their relationship to Dean and Castiel's, but I'm interested in this as well.

It makes me want to explore how Cas left Dean in Purgatory (thinking it was for his own good?) and compare that to Sam wanting to leave Dean now, but not doing so. Makes me wonder what the end of their respective tales will be - with Cas "not making it" because he let go (???) against Sam, who keeps making all these noises about preferring a normal life and wanting to go back to it. I feel like there's got to be a contrasting storyline in there works here, if it can be teased out somehow.