They said they think on it, but decided to not to, cause a "nature" themed axe, would not fit warrior fantasy, but a shadow sword theme would, when they could have simple said the axe got corrupted by sargeras blood/fel magic, becoming even stronger.
Case in point, big problem with classes/specs those days is how the devs decide, arbitrary, what fit and what don't fit in the class fantasy, based on their own taste and short-sigh, so any future class will suffer from that