I've been reading a little TtA theory, saying Iron is overrated. And I can see where they're coming from. Sure, resource production might be vital in just about every strategy, but Iron itself is expensive (5 science is more expensive than any age I tech except peaceful change of government and Code of Laws, AND it's 5 resources, less efficient than Bronze). You just need to be a little more clever, because you can't just stick 5-6 guys onto Bronze and expect to have no problems whatsoever.
I played around on my solo games and found myself being better able to manage resources even without Iron.
I still think that it's damned handy, but I can believe that it's overrated. What could you do in place of the action used to discover Iron and upgrade one mine to gain 1 Resource/turn in Age I and beyond?
Take and play Engineering Genius to gain 3-5 Resources
Take and play Mineral Deposits to gain 2-4 Resources
Take and play Ideal Building Site to gain 2-4 Resources
Take and play Patriotism to gain 2-4 Resources
Discover Masonry and gain 1 Resource/urban building built
Discover Architecture and gain even more Resources for urban buildings built
I guess it depends on opportunity. Getting it early in Age I is of a great benefit, because that 1 Resource/turn easily earns you double-digits. It's still pretty handy at the end of Age I, but I could see how someone may want to save his Science for Coal.
Part of the game is also card management. I've gotten caught up in taking technology cards, but they do no good if your Science isn't strong. The action cards can help you out with those.
I do get a little annoyed at how I feel like I'm falling backward when upgrading mines. I spend 3 to upgrade. I then gain 1 extra. So, I net -2 Resources every time I upgrade a mine. I won't see that investment again for another 2 turns. In the meantime, I could have built a Lab or more military or completed my Basilica.
I may have to read up on some of these theories. It'll drive my wife nuts. She already doesn't like that I've improved my understanding of the game by playing it online.