Okay status update with the new build
After the questline ending with the sewer dungeon, Horde can walk around the city. You basically bribe the Kirin Tor into letting you in because of a magic thing you looted from the last boss that they want. Most services aren’t available (vendors for like ammo and such are tho) and you can’t earn rep with the Kirin Tor, but the guards don’t attack Horde players
I want to emphasize again that most city features do not work for Horde, but I’m not really a fan of this. I guess they figured Dal was too iconic and fan-favorite to exclude it.