There are (or were) an incredible amount of man made "wonders" in the world.
So it is basically impossible to have them all in the game.
Furthermore they should represent many cultures from around the world and should represent styles from ancient times 'till now.
So I skipped most of the European and Middle Eastern/Egypt ones, how beautiful or interesting they may be, as they are already heavily represented.
Of the ones I could choose from I only took 7 and will add 3 from the "other" category, but there are so many, many more I could come up with.
The 7 ones I took from the list in no specific order:
1 Statue of Zeus (Olympia, Greece) An exception, because it completes the ancient 7 wonders of the world.
2 Borobodur (Java, Indonesia) Understandable they went with Angkor Wat as a wonder in the Khmer/Indonesia DLC but this one deserves a spot too.
3 Moai (Rapa Nui/Easter Isle, Pacific) Would be cool to have a 1 tile isle wonder.
4 Machu Picchu (Peru) A ruined city on top of a mountain in beautiful surroundings will be hard to put in this version of the game with the whole 1 tile wonders, but I trust Firaxis to come up with something.
5 Porcelain Tower (Nanjing, China) Sometimes named as one of the 7 wonders of the Medieval Age and was recently rebuild.
6 Great Mosque of Djenné (Mali, Africa) One of the most famous landmarks of Africa.
7 Brandenburger Gate (Berlin, Germany) A much better building to represent Germany in stead of the symbolic Ruhr Valley wonder (in my opinion).
And the other three I would like to nominate also in no specific order:
8 Khujaraho Monuments (Madhra Pradesh, India) stunning Hindu/Jaina temple complex.
9 Shwedagon Pagoda (Yangon, Myanmar or/also Rangoon, Burma) The beautiful and enormous golden stupa.
10 Göbekli Tepe (SE Anatolia, Turkey) made during the 8th-10th millennium BC!!!! The worlds oldest known megaliths.
And this list excludes any modern age wonders and up of which there should also be added some.