You have quite the imagination with some of this stuff. I really hope your mod works out. I wish more people were interested in mine.
Now, to address some of the things you wrote.
I'm afraid actually that there probably aren't any good aerial views of Black Mesa. Huge on the inside, but I don't think there were any good views from the outside. In that regard, I think it's probably very similar to Civ 5's Petra wonder.
I've never heard of the Lotus Temple or Eden Project--they look amazing! They should be wonders for the rest of Civ 5 probably.
Now, here was something I was looking for last week for you but couldn't find:
https://greg.org/archive/2008/08/04...-mines-are-alive-with-the-sound-of-music.html
This is from a scene early in The Postman. The evil army watches The Sound of Music in a big strip mine. And you were talking about having a giant crater or acid pit. What you're describing sounds a whole lot like that.
Here's an idea for your fallout bug: maybe you could create alternate versions of all the standard features. There's forests, jungles, marshes, etc, so just add in radiated forests, jungles, marshes, etc. Not sure if that would work or not because the game would have to know to replace a forest feature with a radiated forest, a jungle with a radiated jungle, etc.
You might also consider variable fallout strength--some that do 5 damage a turn, some 10, some 20 or 30.
If you're going to make a garbage island or something, I would say it should probably be a detrimental feature, reducing the food of whatever tile it's on.
I think the turtle fits right in with the rest of the mod. If you're going to have all these different apocalyptic natural wonders and everything, why not a giant metal turtle too?
And again, you could reserve some of these for a separate mod if you feel it necessary.
For the desert raider capital, I think I prefer the color of the first one. It looks the reddest to me, and I think it should probably be redder still. I'd make it bigger though if you can.
Ok, last thing.
Once again, how do you zoom in so close? What setting do you use to do that? Is it some particular editor or something?