Something with "Metro" in the name.
Like,
Metropola.
Metropolaris.
Metrodyne.
Or maybe some reference to time since the game is really about cities evolving over time.
So like,
Chronicity.
Chronopolis.
I'd caution you against that banner, maybe. It's beautiful, and uses the in-game art style which is great, but to my eye it's not representative of what the actual game looks like. That picture implies a depth of field, while the actual game is on a flat 2d plane with no depth of that sort. So while banners don't need to be 100% reflective of gameplay, because the art style in the banner is so close to the game, there might be some cause for.....I dunno, confusion, disappointment? I guess my point is, that banner image looks cooler and more dynamic than the actual display of the game itself. You don't want your banner to put your actual design to shame. If I knew nothing about your game but that banner and it piqued my interest and I went to investigate the game and saw the two don't match....I might feel, at best, somewhat disappointed and at worst, somewhat misled.
Just my two cents.
I have thought about your name suggestions, (along with others) with a couple friends the last day and finally decided on "Antimatter" for reasons I expose on my last update
https://www.kickstarter.com/projects/geopi/war-industry-a-sandbox-city-builder-with-physics/posts/2899353 thank you btw ( though I immediatly ruled out anything with "metro" because we are currently flooded with metroidvania games).
Regarding the banner, I get your point it is maybe too close to the art style used in the game blurring the conception on how it would look like. I could either used a completely differnet art style for the banner, but I didn't simply because my skill is very limited for the moment.
The other main reason is this banner isn't that far from the visual ingame (which overlap the "against" argument but anyway..), I even used in-game design in the drawing and buildings are basically the same. For the 2D depth I have developped some weeks ago the parallax manager so there is currently 2 layers of environnement backgrounds. With the progression of development, the banner will look very close to ingame gameplay, but most of my last screenshots have parallax desactivated to show very specific things and you have maybe missed parallax.
However I won't be able to counter all your arguments, and surely I need to make some disambiguity, I will solve this by making the exact same scene shown in the banner, in the game , and show it as the first screenshot. This can be a curious thing to see as well.
Finally, a banner is always a lure, what is important at this stage is to make someone click this is the only place where misleading is actually an end, where you compete with deceitful banners. My game uses a new engine, hasn't much arts assets yet and no concept arts, I provide a lot of description and make regular update in my devlog, I feel morally OK if I mislead some users that will waste a few seconds on the internet as long I don't deceive the one who have shown deeper interest in my project.
There is so much to do on the visual side of my game, it represents no more than 1/10th of my current workload, your observation is relevant and I am confident to make the in-game graphics as close to the ones shown in the banner, this should be my goal.