@dh_epic:
Well, first of all I am not so sure about whether saltpeter really has been that abundant as some people in this thread claim it has been.
There has been at least one war called the "saltpeter war" between Chile and another country.
Guano, as a source for nitrates (saltpeter is a form of nitrate, AFAIK - without being a chemist) was collected large scale by European nations up to the late 1800's.
Sure, you could get it as well from animal excrements and so on, but from what I've read about it, I got some doubts that you (prior to the establishment of large scale chemistry industries) could have got it in countable quantities at your local grocer.
However, this is not that much the point.
The arguments you brought in to justify not to need any ressource for building gunpowder based units could be used against making horses a ressource as well, couldn't they?
Up to and including cavalry and cossacks, the horse is THE one vital ressource to create fast and powerful units.
Now, this would make the big empire even more powerful, as you can expect the bigger empire to have higher chances to get those units. The smaller empire therefore has less chances to get them. Nobody seems to complain about this, no?
Once again, where is the point in having Stone as a ressource then? The bigger empire will have much bigger chances to have Stone as a ressource and therefore to get the World and National Wonders which are 50% off by having it.
The bigger empire therefore will be the one to build those wonders
- and some units to defend themselves
- and some other buildings to improve their science or their income and so on.
Yes, the bigger empire will have just better chances to get certain things - if compared to a equally well managed smaller empire.
This is just the nature of the game.
In Civ3 (once again, without any attempt to glorify this badly implemented game) the lack of saltpeter could offer you with some nice challenges.
As I see it, in Civ4 it is only bee-lining to the muskets and grenadiers and out of a sudden, you get a new deck - by the way, something which the AI is not very good at.
So, to abstain from needing ressources for a certain category of units just makes the game easier for the human, not for the cpu.
The arguments you've brought ultimately lead to the abolition of strategic ressources if not all other ressources as well, as far as I see it.
It is just the very nature of a ressource concept that they have to be scarce to a certain degree. If they were not, why have them at all?
Sure, I clearly see that there are some losers out there complaing about the mean game, not throwing each and everything at them when they want to have it. But, ultimately, this leads us to getting rid of ressources in the next sequel.
To be honest, to defend the abolition of saltpeter (or, rubber and so on) sounds just like some kind of short-term conservatism. Oh, this is the concept as was delivered. Just do not change it. Even don't think about other ways.
Yes, it is the concept as it was implemented in the game. Does that mean that it would be the only viable concept? I severely doubt that.