I finally got exalted with the Honorbound on my Horde character, and unlocked the Mag'har Orc allied race.
The scenario itself was really neat. You go back to the alternate Draenor, this time twenty or thirty years after the events in Warlords of Draenor.
In this timeline, the Draenei became fanatical members of the Lightbound under High Exarch Yrel. They seek to convert everyone on Draenor to the Light. You have to rescue the last remnants of the Mag'har from them and bring them to Azeroth.
It's a really interesting set up. The real question is if Blizzard will do anything with this. I could see another expansion based around the Lightbound invading Azeroth. But perhaps a better method might be like how Star Trek used their Mirror Universe. Save it for occasional interaction, but don't focus on it intensely. A bit like how the Infinite Dragonflight was used.
This scenario was excellently done, and it's worth grinding rep with the Honorbound on a Horde character to see it.