The Alliance has not been a threat of the Horde during this way because of what you yourself have pointed out:
The end of the war without the Horde or the Alliance facing any consequences for their actions during it is mostly one sided indeed. In the Horde’s favor.
No different from yourself wanting the Horde to have gotten the last shots in and not wanting the Horde to get hit back for it just because Sylvanas was evil all along.
- Deathstalker Commander Belmont says: Your tree... was just the beginning.
Blizzard has the Horde defile the dead at Darkshore and blight the land that the Horde wrongfully tried to steal and keep. Blizzard doubled down on the Horde’s sins with a warfront framed by the charred husk of Teldrassil as a skybox.
Orcs, Trolls, and Blood Elves along with the Forsaken and Goblins all continue to support the Horde forces at Darkshore while basking under a monument to Horde’s depravity there at.
On top of everything listed above, this is how the Horde is presented in the Alliance introduction to the Darkshore Warfront, using prisoners at Darkshore as target practice:
