I certainly hope they write him in, if for no other reason it would be great just to tie everything that has happened over the years together. Things like that is what helps the entire world feel much more like a world rather than just an expansion piece you play and then forget.
I also agree that if they are going to have him die at some point, this would be an honorable way to do it. I would much rather see a warrior go out as a warrior than to see him just die of old age, especially one that lost what Saurfang has over the years.