There might not even be the same Gorosei type system or even a WG at all, though the revs want to preserve stability. My two cents:
1) The Marines absolutely need to be reformed and act as power separate from the government, hopefully with Coby or Fujitora as Fleet Admiral, anyone with more honorable / blind type of justice.
2) Vivi is an excellent candidate for uniting everyone together with her diplomacy. However, she may not want to be the figure at the very top. Power corrupts an individual like that and can make them grow complacent, losing sight of the goals.
3) We should be careful about Dragon. It's possible he may decline a seat at the table once the revolution is over. He never really striked to me as wanting a position of power, just dismantling the Celestial Dragons. We'll see what happens.
4) Absolutely give Vegapunk or a surviving satellite Ministry of Science and lead the future development of the world.
5) The Reviere should still take place and perhaps more often if possible.
The world of piracy will start coming to an end if we get a fair justice system. If prosperity increases and oppression is eliminated, then people can actually live out their normal lives without fear. There will be significantly less overall crime and less desire for people to take to the seas other than travel or adventure. Pirates are not supposed to be the good guys in the story, but Luffy should remain the ultimate symbol of freedom.
