I know this is looking into the future but what about the first fusion power plant as a world wonder; which can be built after researching the technology fusion?
It could bring the same benefits as the TGD but also with the added bonus of adding 3 happy faces (maybe 3 health as well) in all cities, an increase of 10% in wealth and research for all cities and starts a double golden age.
I know this seems a bit over powering but if the techs stay the same the game is most likely over by that point so it is hardly a game breaker. But if they do add extra technologies the first fusion power plant world wonder should still give the happy, health, golden age and TGD benefits.
It could bring the same benefits as the TGD but also with the added bonus of adding 3 happy faces (maybe 3 health as well) in all cities, an increase of 10% in wealth and research for all cities and starts a double golden age.
I know this seems a bit over powering but if the techs stay the same the game is most likely over by that point so it is hardly a game breaker. But if they do add extra technologies the first fusion power plant world wonder should still give the happy, health, golden age and TGD benefits.