Following the trend of suggestions to make Wilderness content more "optional" and feel less like players are "coerced" to engage with the Wilderness, here is my suggestion for how to change the Voidwaker.
Korasi's Sword is the same as the Voidwaker when used in PvM, however, when used against another player, its special attack is much much weaker.
However, Korasi's Sword can be obtained outside of the Wilderness. Either from a quest or a non-Wildy PvM boss. It could also be untradeable.
The goal is to give players a non-Wildy option for the Voidwaker.
This is the best way to do it, if we choose to go down this route.
I'm personally for it, because it would reduce resentment towards PvP and is a form of goodwill towards the community.
However, I believe it's only taking that incentive away from players who did not wish to engage with it in the first place.
Players who DO want to engage with the Wilderness, will still have incentive to engage with the Wilderness.
There are other, better ways we can create incentive for players to engage with the Wilderness.