"We found that when you're playing for the military victory, it's a very active, aggressive playstyle. You really interacted with all the nations," Beach noted. "But when you played for a cultural victory before it was very passive. You built a few amazing cities, but you just weren't interacting with the other empires in the world. We felt that was a real missed opportunity. We've emphasized in Brave New World that you're going to build a culture that's really the envy of the rest of the world. You not only have to build it, you have to spread it to the rest of the world."
This is all against the backdrop of the new diplomatic victory system as well. Starting around the time the Renaissance starts to give way to the Industrial era, the nations make a World Congress. This doesn't result in an immediate victory, but it does introduce the concept of proposals--specialized rule changes. You'll have a vote to cast in these matters, such as voting against anti-whaling resolutions if that's your primary source of income.
Shirk said these resolutions can be "cooperative or vindictive" depending on your play style, and they can be used to shape the kind of victory you want to attain. In this way, the diplomacy system doesn't just impact its own victory, but it can manage to touch
Civilization V 'Brave New World'