Yes, there are rare instance of wonders which should be outside of city, like Giza Pyramid or Taj Mahal, but most of them fit more the inside part of cities.
Also exploiting everything have some bads effects sometimes, Giza Pyramid is surrounded by farmlands, coastal wonders need to be build beside a maximum of land tiles ... It don't make sense.

Also a bit of city building, planning, and puzzle are fun in 4X.

In term of suggestions :

- There is the usual "counting as", but I would avoid it,because this feature is overused already in emblematic quarters (highly overused, still don't t know why a Carthaginian Cothon count as a farmer ...when it's just exploiting food as every harbors anyway), and keeping it only when it make sense. Like if they add a wonder based on an harbor one day, it would make sense it count as harbor.

In the current roster of wonders, I eventually can see Machu Picchu counting as farmer (because this wonder is full of terrace farms), or Great Zimbabwe counting as Hamlet because it's a little city or Alexandria Lighthouse count as a garrison because there was a fort at its bottom.

- More specific exploitation capability, to make the Wonder feels more unique. Mausoleum at Halicarnassus only exploiting Science for exemple.

- One feature suggested by someone on Reddit which was interesting, was to make count some wonders as "Joker", basically a Wonder would fill any adjacency condition from another quarter.

- My personal suggestion was to make Fame distribution more strategic and about city planning on the long run, instead of a flat gain. Like u receive X fame per Markets around Hanging Gardens of Babylon , X fame per harbors in the same territory than Alexandria Lighthouse , X fame per river in the same territory than Giza Pyramid.

- In term of crazy placement conditions, we could imagine than wonder exploit everything around when they replace the city center : Pyramid of the Sun, Forbidden City, Topkapi Palace, Palace of Versailles, Big Ben. They definetly feels like centers of capital and cities.

- Some current placements are weird, why Liberty Island need to be sticked beside the coastal land ?

- Some aspect could be stretched in term of thematics. Giza should be built far from city BUT it's true than some few quarters surrounded pyramids, at first the builders, later the looters.

So having Giza Pyramid acting as 1 tile range anchor point for ONE type of quarters (makers here), would be an interesting feature. Could be combined with a feature of giving industry to the arid/desert tiles of the territory.

- Congress of Humankind Headquarters could have a placement related to Embassy ?  

- Some wonders should just have some adjacencies because they should be somewhere in the city, like Eiffel Tower, Empire State building, Notre-Dame.

- Minor flaw about the Wonders which can be built on mountains even if I love that feature (like Machu Picchu, and Christ Redeemer). These wonders are unreachable by land troops, which don't really make sense, and make them immune to raiding. And decrease the feeling of players to modify the world and gaining access to a tile which was not reachable before.

Would love to see some singular wonders like the gigantic Chinese treasure ship which is highlighted in early modern cinematic. A wonder you can move from territory to territory in the sea, but is still a building. Or the Murud-Janira sea fort. An harbor wonder (Venetian Arsenal ? ). A fort wonder, a lake tile wonder, ... etc.