Yeah, I was a bit rambling. I know.
But to put it in some more practical terms:
As on startup, a player can choose his map, or put on the random option of course. Let's assume the choices are "barren", "marginal", "terrestrial".
Climate options could mostly stay the same, but let's put "cold", "warm", "temperate" and "rocky" in the equation for now.
And for sealevel (perhaps renamed to seasize) the options "none", "small", "medium" and "large".
I don't know if the game would allow for more startup options, but with the 3 above already a lot of different maps could be accomplished. Ideally a fourth option to choose the density (or lack of) of the atmosphere would make the choice complete.
For instance "barren", "rocky" and "none" would give a player a map like our own moon, while "barren", "cold" and "large" would give a player a map like Europa, the icemoon around Jupiter with a liquid ocean under its icepack.
Also, some options could exclude other options like already is done with the ice_age map in Civ4.
According to the things I've read sofar in modthreads, we're stuck with the number of different terraintypes the game has (supposed to be hardcoded). Thus all the current ones are to be used in combination to create believable maps. Like a "marginal", "temperate" and "none/small" map would make use of desert and desert hills, with perhaps some small seas in it (a Marslike planet so to speak), while a fully terrestrial map ("terrestrial", "warm/temperate" and "medium/large") could use almost all terrain types. In this system only one, perhaps two, terrain type(s) should be converted to a dedicated sort of vacuum-style graphic. The rest could be used in combo's, probably with some change graphicswise as well to create some scifi eerieness.
That's it for the maps.
As on how the environment adjusts the way things can be build/reasearched, I think you already seem to understand what I meant.
For instance take a fictive tech Bio-engineering. In a terrestrial world this would allow the introduction of certain earth farm animals on the open, while on a marginal world the same could apply to domed pastures. On iceworlds of course this could not apply and the tech would be useless for agricultural purposes then. Instead a sort of "aquasphere-seeding" tech could allow the spreading of fish farms under the icepacks. (I admit that this sort of map wouldn't be popular graphicwise
). Overall the idea is that since we're talking about a whole new world, earth crop/animal graphics could be used (where applyable) to show the terraforming of his new world to the player, but of course with other (lower) yields then we're used from Civ4.
Also, in case of base/city facilities, the terrain plot on which it is founded could mark codewise (and in combination with the mapchoices) what sort of facilities can be build in this settlement. A barren plot would give a starting city immediately a dome of course. Same with a sea-based settlement.
Hope I have made things a bit more clear now.