Ding! One of my writer friends has been working on a fantasy novel for a long time. The first time I read it I was all, "This is so freaking slashable. I'll write slash for you ;)" She didn't take it quite so positively and tried to write it out before she realized that she couldn't and just accepted that it was slashable. (She had the guys cutting each other's clothes off deliberately in a fight. Seriously.) It took her a few years with me working on her though ("Slashers are producing free advertisements, build a fan community.")

It's not even that Sam and Dean's relationship is what's drawn the fans; it's that it if simply impossible to describe the show without it. Any changes that could be made would make it worse, not better. (like them not being brothers. Then we'd still have a very slashable buddy cop type show) Supernatural without the slashy subtext isn't Supernatural, couldn't even vaguely resemble it. The show is stuck with its slashers and it seems like they've accepted that.