Just a bit of feedback on the changes; it occurs to me that ironbone is more an expression of orcish shamanistic tendencies, whereas the blacksmoke furnace is an expression of their industrial tendencies. It just seems weird to me that the twain shall meet there. I would advocate leaving the furnace be on that account. Unless there's something I'm missing, of course; I haven't played orcs in at least 6 months.
I actually really like that sentiment; the description of the Taiga Orcs in the manual definitely talks about the conflict between the old ways and the new ways.
The gotcha is that the blacksmoke furnace is what allows orcs to remove rust from iron and steel. However your trading partners only bring the rusty iron, your enemies tend to bring mithril and steel, and your workshops can only make ironbone and bloodsteel at this point. In my last game (on an iron-free map), actually getting those first couple of iron bars took a long, long time, despite the fact that I was slowly cladding my troops in mithril (from hunting elves).
So the blacksmoke furnace is a bottle-neck, and it's not intended to one. You need iron to make the furnance to clean your rusty iron (which orcs are swimming in).
We could have a reaction somewhere that converts ironbone to iron, that would solve the bottleneck, keep the thematic nature of the building materials, and not change gameplay balance at all. However I haven't figured out where that's best suited to run; suggestions definitely welcome! (If nothing else we could add a 'exchange 3 ironbone for 2 iron' at the Freelancer's, but it doesn't really feel appropriate there...)
~ T