Peng Qi
Emperor
It could be done in a really simple manner:
1 resource of a type = 10 (+/- based on map size?) total units that require it. So if you had 1 iron and 1 horses, you could have 10 knights or 10 horsemen and 10 swordsmen or 5 of each, and so on. This could be kept track of in your military adviser and could pop up in a tooltip when you select the unit to be built, such as: Swordsman (requires iron, 6 left). This would have the added benefit of copper not becoming totally pointless the second you have iron, since it would let you maintain more metal-required units.
1 resource of a type = +50% total bonus to all wonders being built that require it (max 50%/wonder), so if you have one marble and are building the Parthenon and the Temple of Artemis, each would only get a +25% bonus.
1 resource of a type = 10 cities get a happy/healthy bonus for that resource would be a bit too complicated if you ask me, thanks to needing to micromanage which cities get the bonus. The above do not require any micro other than not using up all of your iron if you intend to build something that requires it soon.
1 resource of a type = 10 (+/- based on map size?) total units that require it. So if you had 1 iron and 1 horses, you could have 10 knights or 10 horsemen and 10 swordsmen or 5 of each, and so on. This could be kept track of in your military adviser and could pop up in a tooltip when you select the unit to be built, such as: Swordsman (requires iron, 6 left). This would have the added benefit of copper not becoming totally pointless the second you have iron, since it would let you maintain more metal-required units.
1 resource of a type = +50% total bonus to all wonders being built that require it (max 50%/wonder), so if you have one marble and are building the Parthenon and the Temple of Artemis, each would only get a +25% bonus.
1 resource of a type = 10 cities get a happy/healthy bonus for that resource would be a bit too complicated if you ask me, thanks to needing to micromanage which cities get the bonus. The above do not require any micro other than not using up all of your iron if you intend to build something that requires it soon.