Originally Posted by
Super Dickmann
Killing Anduin would only be worthwhile if it was accompanied with an overall writing change to take into account that different groups and leaders have incompatible goals, beliefs and material interests and so not every fight needs to be blanket good and evil. As this won't happen given the writing staff, killing him has no long term benefit since someone else would just enter into the Anduin role, just like Anduin inherited a lot of Thrall's story handicaps. On the other hand, as inevitable as it is, you jump an extra shark past the ones you've already jumped by having a guy be stabbed by a soulstealing runeblade forged by the devil himself only for him to recover fairly harmlessly.
Mind, there's no real loss in killing him either, and the vacuum would be a useful storytelling opportunity even for the current staff. It just won't happen.