Like most of the factions in OWB they are mostly made up mostly.
The Iron Alliance from Wasteland 2 is just a band of raiders running a protection racket nothing major.
But their big thing is that they wear heavy suits of metal armor making them a bitch to deal with in combat.
I don't think it is power armor in WL2 just metal plate, the leader portrait in OWB is the same portrait you get when talking to their leader in WL2.
And this is translated to Hoi by giving them power armor and little buffs and a bit of lore for why they and only they have power armor.
I think they should get a focus tree, they are really interesting and are good for a world conquest as the PA tech lets you keep up with the big boys late game and curb stomp your neighbors early game.