Thats just Lannister blood.
The pride is maimed at this point.
There were losses for Team Lannister no doubt about it, but while the House lost some, it never came into danger for its existance in the same way that the Starks are.
Winterfell was sacked and burned, but granite doesn't burn easily. And the pack is still mostly alive, even though long leagues separate them.
Well, I think that Jon isn't look so good at the moment, although I can't imagine that Martin would kill off that character at this time. But you are right that most of the Stark losses have in many regards been superficial.
And his legacy is decided by those who fight on for his families sake.
Yes and no. I think that his legacy as a failure of a king will live on south of the Neck regardless of how it goes in the North. The remaining Starks may save his memory in the North but I don't think they'll be able to make much of an influence in the South.
The wolves will return.
Since most of those he left behind were left behind to die in a ditch as winter set in I'm not sure there will be alot of people to ask. But while everyone makes mistakes, Robb's mistakes were very costly and were not once in a while but rather regular.