It's nice to see the Sam-Cas bond explored at all. They are natural friends and I honestly believe at this point they have a better friendship than Cas does with Dean. Sam just gets him and accepts him and it's lovely.
I used to ship Destiel like whoa but the longer the series goes on the more it occurs to me that Dean doesn't really understand Cas and he doesn't notice or mind this. He won't adjust his expectations because Cas is Other, he simply expects Cas to meet his expectations and, when he doesn't, he dismisses him. Because Cas isn't human he may not feel he owes him any care (at least not emotionally). Cas can take care of himself kinda deal. Or Cas doesn't have complex emotions. He has said some shitful things to Cas (No one cares if you're hurting!) and yet it's still the biggest ship in the fandom. I do not get this.
It's Sam who is patient with Cas, who doesn't expect him to change to meet Sam's expectations. It's Sam who knows Cas means well even when he messes up because Sam knows what it's like to mean well and mess up that badly. I think Sam sees Cas as a kindred spirit, someone who has been where he has been, and so defends him because he knows just how bad that feels and also how it doesn't mean Cas is worthless (as Dean makes him feel sometimes).
So, yeah, I can't ship Destiel any more, it's too destructive to Cas' psyche and I don't think Dean would every budge an inch to meet Cas part way, but Sassy has great potential for a relationship on equal terms.
like, omg did you just read my soul or something?!! I could not have put that any better myself! There was a time when I used to ship Destiel too, but my perspective changed as the seasons went on...I think the final straw for me was that exact moment you mentioned, in season 7, when Cas is clearly deeply hurt and distressed at the memory of what he did as "God!Cas" and all bloody Dean can do is VERY harshly remind him it was all his fault and say "Nobody cares that you're broken!" That painful moment utterly destroyed my support of the Destiel ship...I don't care how pissed you are at someone, if you truly love someone you're supposed to be there when they need you; you do NOT kick them when they're down!! Not even friends do that!! My heart just shattered for Cas in that scene...
So, yup, totally a Sastiel (close friendship) shipper now!!