Lorewise the Dark Iron clan has always been known for their sorcery so Mage is the first class to come to mind.
I’d think a close second would be Shaman, not because of the once often mentioned summoning of Ragnaros (which incidentally was performed by mages who didn’t entirely know what they were doing) but because they’ve been under the thumb of an Elemental Lord for years now, and are quite clearly very close to the element of fire.
The discipline itself was originally created for the purpose of violent rebellion.
Yeah I would go with a Fire Mage or Destruction Warlock for lore. They best represent the 8 that summoned Ragnaros. I think technically they’re listed as sorcerers so either class works.
Paladin is surprisingly suitable for Dark Irons with all the fiery abilities they have. Wake of Ashes and Shield of Vengeance, hell radiant damage itself is holy and fire combined.
I went with a paladin. A lady paladin in fact! There’s plenty of overlap between the light and fire motifs. And paladins have a lot of armor sets with a fiery bent to them. Also the DID pally mount looks awesome.
Dark Irons are more secretive, cunning, and intellectual than the other two major clans. Prior leaders like Thaurissan and Modgud were both sorcerers, and Moira herself is a Priest.
In classic there were Dark Iron Warlocks and Mages, Paladins and Priests in BRD, etc.
If I were you, I would pick a clothie, maybe even a Shadow Priest. Some Dark Irons have a history with the Twiligh’ts Hammer, so void magic would fit perfectly.
I love dwarves, drizzt and archery. So my dark iron hunter fits perfectly as a hero that stands apart from the normal course his breathren tend to follow.