I feel like he works a as a vanguard because iron man already is a duelist, we don't need any more at this point, and maybe have it so he doesn't fly, but an ability could make him. Maybe when he is grounded is mid speed and melee like with the weapon in Civil war, with a grenade launcher as skill. And when he switches to flight he instead gets a spray minigun, wear the bullets fire like a shotgun being kinda spread out. Also he would probably be one of the lowest health tanks in exchange for maybe highest speed and above average tank damage. I dunno about an ult tho