This is simply speculation, mind you, and there are no intentional spoilers written within the confines of this post.
This is a thing of consternation for me, given that Rick Grimes, to me, is the greatest comic book hero/antihero of all time. Better than Spider-Man, Batman, or Superman, Robert Kirkman's central character in this study of studies shows no special qualities required of other comic book characters save for the fact that he always made the best of horrible situations. While the comic would live on without him, it would not be the same, changing abruptly for the worse. Rick's death would signal not only the beginning of the end of his own story, but the end of the co0mi book's run as well. At least at this point.
Rick isn't necessarily the man I would be, but the man I want to be in a situation like he is in, facing down the fires of Hell unflinchingly, and going through with his decisions whether they were good or bad. It would be a shame to end his run here and now.
One of my greatest tribulations in this regard is the fact that there will be an attempt to inject sex into the comic, meaning that mr. Kirkman, the veritable creative wellspring, is running out of ideas and would be desperately clinging to a pet project that would be on the decline nearly ten years after its birth.
Once again, this is simply speculation. I'm not saying this is all true, but if it were, these would be my thoughts and feelings on the matter.