So, the Mag'har . . . [Spoilers?]

[Grumpy Old Man]

With the Iron Horde allying or befriending the Ogres, the Mag'har could have the link needed to recruit them into the Horde.

I totally forgot the ogres. I hope you're right. Since WoD we've know a lot more about their culture and society - there's not only the brutish ogres we ever knew, but also the intelligent, cunning ogre magi with their very unique brand of magic. They would be a nice addition to the allied races list.

[Kralljin]

I'd like to see what they show in the scenario to recruit them. From what we've seen of it, the map, their capital is in Gorgrond and it's a massive iron structure.

Blackrock Clan already had a similiar architecture, heck, someone with basic understanding of construction involving metal and stone probably built HFC in the MU.