In previous incarnations of Civilization V the most important Great Person a player could get was a Scientist, because he could be saved up near the capitol, ready to instantly research those all-important technologies like Electricity or Rifling when the time was right.
Second best, for my play style, was the Engineer that could speed up a wonder that was taking too long to control and I tended to consider the Great Artist and the Prophet fairly useless.
Brave New World changes all that by making cultural victories, based on influence and tourism, a much more interesting way to end a game than the space race or all-out war.
I am playing as Brazil and that means my Golden Age is actually a Carnival that increases the rate at which Great Persons are created by 50 percent for up to 12 turns.
So I am basically stacking up happiness and culture as high as possible while keeping around just a skeleton military crew in order to launch as many Carnivals as possible and then boost my number of Great Artists.
I actually want to get writers and musicians now because they can create great cultural works that I can then put into museums and other buildings in order to gain influence with other races and basically overwhelm them with my heritage.
I still love to get a scientist or an engineer from time to time but playing Brave New World with Brazil artists is now my most powerful weapon.
Of course another faction can deploy a strong military and simply wipe me off the map so I also need to keep up in terms of the arms race, but as long as I continue to churn out paintings and symphonies, I am pretty much set to become the benevolent cultural ruler of the Civilization V world.