Last Hearth
Member
... really?
ASOSThe only reason I think it might have less of an impact than Ned's death is because I feel there are a lot more book readers now.
But there is no way Robb's death will be viewed similarly as Renly's. Robb is a favourite for many people, and people feel revenge for what happened to Ned lays in his hands. he represents the Starks for many people, and many people are rooting for the Starks. Plus Robb and Cat are two main characters who have been in this show since episode 1, and when they die, people aren't going to be like, "Oh ok."
I doubt the fact that more Northerners haven't been established will be the difference between "HOOOOOOOOLY SHIT WTF" and "eh ..."
ASOS
The show has already made his cause almost hopeless by having the Karstarks take away "half his men". Which btw is ridiculous. But the hope for the Starks didn't just lie in the Robb, but all solidarity of the North behind his cause. He can die and the cause can still continue. But after the RW the cause is shattered, because the Stark loyalist were almost all murdered there. Then entire Northern host was slaughtered. The RW killed all hope. Which is why many people like myself couldn't even turn the page after reading it and had to take a break. There is almost no chance the show can accomplish this because they haven't set up the story sufficiently to earn that moment.