I dont think DC is so far gone that they'd write him off either, but I can no longer completely rule it out. Now it just seems unlikely. Unlikely, but possible, which I wouldn't have said a year ago.
But no, I think Nightwing's profile is too big for getting rid of him. Otherwise Didio likely would've managed it long before this. But just the fact that posters like you are saying you wish DC had killed him might be that DC is winning, getting us to want a mercy killing. Didio's bosses can't be mad at him if he's just giving the fans what they want and the book isn't selling anyway. And I do believe the sales are starting to drop now, arent they?