Since the Gerudo have gotten an update in their appearance, especially in regards to the iron knuckle, I've been thinking up some ideas for diversity for the latter. Here is what the new iron knuckles look like:
Clearly an imposing foe on its own, but what if it had variants? This greataxe wielder could be a purely close-range, damaged focused unit with decent armor in order to shrug off a few blows before going down, after of course taking down many of its assailants.
Sword-and-Shield Iron Knuckle
Focusing more on defense than offense, these iron knuckles could act as guards, slowing down enemy forces with their giant shields while Gerudo archers rain death upon their enemies. Being rather slow, they would be ill-suited for fighting archers, and horsemen would be able to outmaneuver rather easily, though a head-on charge would prove dangerous for them. These iron knuckles could be based upon those that appeared earlier in the series as well as the OoT beta, as well the suit that makes an appearance in MM.
Ball-and-Chain Iron Knuckle
A unit that could act as a ranged unit for the iron knuckles. They would deal high damage from a moderate range, making them excellent against oncoming melee attackers, but would be inferior to archers as well as any opponent that gets too close. Could possess the weakest armor of all the iron knuckles. This design is based partly on Onix, as well as the fact that the new iron knuckles appear to be wearing silver gauntlets, which in Hyrule Warriors is associated with the ball-and-chain weapon.
Grappler Iron Knuckle
A pure, unarmed melee variant that engages foes with oversized silver/golden gauntlets. Punches send foes flying, and they attack relatively fast for their size, and could in fact be the fastest of the iron knuckles in terms of overall speed.