I see what Steph is talking about when he says that he needs advice on mechanisms and not scenarios. I think Ondskan is really asking for a mechanism kind of like the Civ III global warming, only much expanded. This would probably be a little tough to control, but would be interesting to implement. Perhaps the 'scenario.stph' would have values close to how volcanos erupt or how resources disappear implemented into the 'terrain change,' and even a prerequisite, to enable the before mentioned era-specific changes. Ondskan, correct me if I'm wrong.
As for aforementioned ambition,

, I'm glad to see you are trying to really create something really great, and I'm sure once we start seeing what you have in mind we'll throw some really big stuff at you.
And, several ideas for the tech tree. First up: please make the prerequisite have an OR option. This would allow modders to have several different cultures access the same tech mid-tree, which would be a boon. Secondly: someone mentioned Empire Earth's (or a similar game's) tech progression, which is quite expansive (I loved EE2), and with that large number of eras, an idea comes to mind. Why have three or four hybrid eras where a modder has to squeeze in tons of techs when you could just have mini-eras? Just allow the option of creating less or more eras and the modders will either use more or less eras according to their preference.
I'm trying to think outside the box here, but perhaps I'm still sticking too close to Civ III. Darn, why does it have to be THE turn based strategy game of all time?
EDIT: Darn. My first real crosspost.