I simply…do not see Dean giving up on Castiel so easily. He cares too much, Castiel is too important to him, for Dean to throw it in without a fight. And I am hoping—hoping—that since the show has been about falling and redeeming, Castiel will get his chance as well.

This is where I am with it and like you, I can't spend the hiatus agonizing over another possibility. Another possibility makes to little sense and is too WTF to me to even parse it -- I see Dean how I see him and see Cas the way I see him and it's moot. Dean won't give up on Castiel.

I agree with a lot of what you're saying, especially that Sam and Dean messed it up towards Castiel, but Castiel made all his own decisions and Sam and Dean didn't cause this, it was everyone's issues compounding everyone else's. The prevailing wind viewpoint among Castiel fans seems to be that the Winchesters betrayed Castiel -- but I'm watching a different version of the show with a different version of Sam and Dean and Castiel. I feel terrible for Cas and understand why he did what he did and this isn't a situation where the word "evil" is operative for me at all, it's heartbreaking. It's in fact the nature of Castiel's culpability that puts this big lump in my throat over how much "family" Castiel has become, part of the chain from John to Dean to Sam to Bobby.