Like I said, a big button that can rewrite any part of reality? Absolutely. At the very least if they tore down the walls between life & death then that would both open up the Shadowlands races as allied races & then death would feel more permanent. How it works now effectively everyone has two lives. Die in the shadowlands & your ineffable soul returns to the Twisting Neather, how it's supposed to.
And Sylvanas would have succeeded at what she vowed: "The World is a Prison & I will set us all free"