Putting Ros's death above Ned Starks might seem weird, but there's a reason behind this. Granted, Ros isn't the most important character in Westeros as a TV creation she benefited massively from the translation from page to screen, largely down to Esme Bianco's performance but this isn't a list of most important deaths, or most shocking moments. It's Joffrey's biggest moments of dickishness, and this particular murder is several magnitudes larger than when he deprived the Stark paterfamilias of his head. The reasoning behind it is simple Ros is an innocent, whereas Ned, however justified in his convictions, is technically guilty of treason. You'd expect him to be punished, and he was going to be it just so happens the punishment was based on a capricious whim completely devoid of political nous. Ros's only crime is being a casualty of Varys and Littlefinger's political machinations she was a pawn offered up to the sadistic little moppet to curry favour, and died what looks like a horrible, elongated death. Knowing Joffrey as we do, you can bet the house that the headshot wasn't the first of those arrows. As Joffrey himself says, he was merciful by giving Ned a quick death. Ros wasn't so lucky, and ended up tied to a bedpost and turned into a pincushion. Nasty stuff.