From what I've read about it, they aren't really killing him off. Just retiring him for a bit to have a replacement, then probably bring him back later. They did that about ten years ago though, so it's old ground.
I don't know why they think they have to keep killing superheroes off. Why not just give them a better quality/quantity of life???
The writers aren't creative enough to actually use the characters and the marketing people think it will boost sales. What they fail to realize is that after so many fake deaths, comic book death is a joke to the readers. Seriously, one time Spider-Man was killed off in one issue and brought back to life the next week. No reader actually believes this or any other comic book death will stick.
Besides, they'll just bring him back when the next movie comes out, if it takes that long, for movie tie-ins.