If that's the case, then the writers really do suck because Sam almost always fails. That's not a hero in my book. In fact, I think they portrayed him for years as such a whiny, self-centered person, he really became unlikable. I've found Dean depressing at times, and occasionally infuriating, but I don't think I've ever actively disliked him because even when he is wrong, they've gone to the trouble to show his viewpoint. Letting Gadreel possess Sam, for example. I really WANTED to dislike him for that, but couldn't because I understood why he did it and I knew he was suffering over the decision every time he lied to Sam. With Sam, on the other hand, it's all too often sheer guesswork, such as his choosing domestic bliss with Amelia over searching for Dean.
At any rate, I think our viewpoints of these characters vary greatly, which is fine.