More and more in recent times, there has been an obsession with characters that have a somewhat mixed morality: The Sopranos did it first, and the likes of Breaking Bad and Dexter have also gone down that path - both with major success. There's nothing wrong with an anti-hero or a character with conflicting ethics, but the key is balance. The problem with Game Of Thrones is that nearly every character is 'grey', and while moral ambiguity isn't necessarily bad - it's fun to see manipulative and conflicted characters, people who you can't really predict - when nearly every character is unpredictable, then that's just boring. The complexity and interest in a character comes from seeing them either put in a position where they thrive, or a position where they don't fit, which is precisely why Ned Stark was the best character, and why Game Of Thrones was as headless as his body after his death. He was the white knight thrust into a world that was so different to him, and the conflict it threw up was what drove the first season, of a man who had such ironclad ethics he'd do what he thought was right, even though it put him in danger. Nowadays in Westeros, there isn't any of that fun: characters have so few morals that you can put them into any position and not be surprised by what they do. It's boring. But then that seems to be what the audience craves nowadays: they don't want black and white characters, they want someone grey. And the show doesn't seem to realise that such characters need to be used in small doses, and you need characters on all levels of the moral spectrum.
