Sid, Please Do Your Own Work...
The choice to include actual world religions seemed bold but in execution was silly and nebulous, just as cultural genera and cultural specificity choices seem silly and nebulous. Why play as a culture when all that signifies a culture is a cultural "alignment motif" and a unit type that might not be useful in the culture's predominant terrain (and hence never would be developed as a sensible elite). It would have been better to permit equipping units as per customization options in Alpha Centauri, and to understand that should (say) Elizabeth the Queen find herself leading Ancient Britons in a jungle kingdom, she would probably reign with some difference than is historically alotted. This might entail that instead of cultural outlooks and units that are provided, rather rulers and nations behave differently depending on what clime their capital is tropic to and a culture's elite unit would be categorised according to terrain rather than era (but remain entirely cultural). Yes, this could degenerate to "Infantry/Elite Infantry", but it needn't.
Despite all this, Civilization 4 is perhaps one of the better offerings that we are permitted to play. While it is largely without strong innovation originating in the so-called brand developer, Civilization 4 behooves armchair generals to consider sparkling graphics and clean presentation. All considered, Sid Meier should look into actually crafting his own games rather than resurrecting old games without granting credit where credit might be due.