I like them cold, dirty, and brutal.
I hate that they are never in the trenches in any artwork.
They should be lined up and covered with gore and mud, backed up by massive artillery and daemon-engines.
They lead a charge with only the butts of their bolters and the occasional bayonet.
They fortify everything with plasteel and electric wire.
They care not for politics, for greed, for lust, or even vengeance. They feel only cold, mechanical disdain for those they face. They are disgusted by the impotence of the Imperium.
They demolish all in their path, an unstoppable war machine, leaving smog and ash wherever they go.
They spit on the corpses of their enemy and loot their armor to repair their own.
The Iron Warriors should be a unifed force of ramshackled and fortified marines. Everything is unpainted except the hazard stripes of their legion and the battle cries of their company.
On their arms are hastly strached tally marks, noting each kill. Their armor is never a complete set, bet every possible mark juxtaposed together.
The Iron Warriors are a legion of desolators, scourging the earth where they walk and trampling the landscape underneath boots and treads. The only sound they make is the boom of artillery, the screams of the fallen, and the crunch of failing armor.
Iron Within, Iron Without!