Slingshot, I like the idea of customer committed into the development. It's now more widely available because of Internet power, still it's a bit limited to us, the game fans here on fans'sites (Apolyton and others).
We already do a lot of useful work with The List and Essentials 5, may be we can do some more on a beta testing. IMHO there is no way we can help on first builds and prototyping.
Firaxis should be more positive with us, trying to list what's in (at this stage) and what's out (definitelly) related to The List suggestion. It's some form of secret revealed to the other companies, but I think Firaxis can survive with it.
If Firaxis can cut off The List enough, I think we can do another, more focused help.
Of course we will have some criticism from players who don't like the chosen way, but it will be a fact of life, at least when the game will be almost finished and revealed.
I think will be better if we don't waste our and Firaxian time with suggestion out of CIV III guidelines, when they will be available.
Some "why this idea doesn't fit" explanation will help to understand Firaxis position against some smart but not proper to CIV III concept.
Every Apolytoner should then understand why his/her dreaming CIV III shouldn't be exactly the same of other millions of customers, and survive with it

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Adm.Naismith AKA mcostant