A lot to digest.
The Spawn is actually an oversight and will be removed.
@Maelstromof Gore: I liked the name and it is the only official name for a Berzerkers warband. But replacing it with a Khorne minded non-WorldEaters formation has merit.
@LemanRusses: Hmmmmmm

@Chaos Leviathan: Huh? Never heard of this. And will it fit? It is a mobile command centre and not a siege engine. Termites, Moles and Hellbores would fit more but tunneling devices aren't mentioned in the book.
@Steve54: Well actuall Iron Warriors ar infamous for being string in assaults and strong in the defence. I see no problem in this as long as the formations are pointed accordingly.
@Titans: Well the Siegelord is big and well shielded. It has time to reach the walls to breach/storm them (but perhabs i will up its shields to 9). It is designed as a walking siegetower/ram.
Besides i came up with ideas for siege themed Reavers and Warhounds.
And i see Titans as to mobile to be stationary artillery pieces. To shell enemy fortresses from adistance there are several other things good for.
But well i could make a non specified IronWarriors armylist.