Wonders should be districts or buildings within districts, not take up whole tiles.

[Captain Potato]

there aren't really super overpowered wonders

One exception to that in my opinion: the colosseum. Other than that I agree wonders are in an alright shape compared to previous games. The tile restriction has been an important balancing mechanism so you can't just spam build them any more. You only build them if the effect is specifically going to benefit your game plan, and that's how it should be.

 

[King Rad]

I like the new system. Are there good ideas that could enhance the current [or future] wonders, sure, but I like that they take up their own tiles and have specific requirements. Again, it adds to the strategy of deciding when to or not to build them.