While the new one looks more natural, the original is more iconic: the colors are exaggerated to make items stand out more clearly.

I think the original looks so much better. I guess I'm tired of the trend in games where they remove most of the color and add some filters to them.

Well, the fan-made mockup has such look because that's the only thing you can do with the screenshot.

Real mod could do much more, e.g. changing textures or models geometries.

It's the whole new cartoony art direction that's weird and off-putting, unfortunately evoking the feel of cheap mobile games.

Here is a real world photo example of what look modern AAA "Civ-like" game could strive for:

http://i.imgur.com/p4XZDeR.jpg

It's possible to be lush and colorful, yet realistic and more mature looking.

100% agree. Reminds me of the Diablo 3 art debate: http://www.diablowiki.net/Art_controversy

I prefer the original. It's more consistent and I don't think realistic graphics are a good fit for something like Civ.

Sort of looks like Rome Total War 2 vs Clash of Clans there.

The 2D isometric art in Civ 2 will always be my favorite, though.