I've noticed that in the new expansion diplomacy seems to work much better than before. What I mean by this is, it is much more easily possible to build partnerships/"alliances" with AIs and create networks of these alliances, and at the same time it's possible to re-engineer and shift alliances as the game proceeds and nuances/quirks pop up in your alliance system. AIs will also adapt to your alliances and even attempt to join in them. Things seem to shift logically now as they never did before.
For example, in my current Ethiopia game (King, yeah I'm still building up my skills) I set up an early alliance with Hiawatha and Augustus against Askia. As soon as I saw Rome expanding too much, taking Jenne from Askia, I shifted to ally with Askia after his denunciation wore off, though I kept my DOF with Augustus temporarily and kept exporting resources to him for large payments per turn. I chose not to renew my alliance with Rome, and it broke down.
I later shifted towards building a coalition against Washington. I was aiming for a cultural victory (I've abandoned this goal in favor of science or Diplomacy at this point, though I completed Piety
) and so I refused to settle the swaths of land around the coastal city-states to my west; Washington settled all those instead (Manifest Destiny repeated!) and became powerful. Conveniently, Washington had been attacking Askia repeatedly, so the Iroquois had grown suspicious of them; I slowly built up the trust of Alexander (to the south of Hiawatha and Washington) and allied with Ramkhamhaeng (who had the most powerful military but was far to the east).
I've just finished my war with Washington as of ten or so turns ago, and successfully took two cities from him and puppeted them, as well as knocked him out of 2nd place in the military rankings; but there is a diplomatic revolution in the making. A while ago, I bribed Ram (72 gold and 2 Horses!) to go after Pacal (the tech leader) but strangely Pacal denounced William (a longstanding enemy of the Iroquois-Ethiopian alliance) and DOFd with me and Hiawatha. Logically, I predicted that this would produce a rift, now the seeds I sowed for temporary gain are beginning to sprout. I later bribed Ram to go after Atilla (a semi-free agent who turned against our alliance but is apparently friendly with me now) as Atilla completely took over Arabia except for one city (they were basically a pariah at one point).
Now Ram has seized the previously Hunnish Mecca as well as swallowed one of my city-state friends. He's fourth in the rankings but I expect him to quickly move up. Greece also turned down a DOF, so I checked the Diplomacy screen and saw that Ram had denounced Hiawatha, so I backstabbed him and got an angry response from Alexander. I'm still friends with him, and he's still at war with Washington, but who knows how long that will last?
Anyways, a general overview of my current situation (if anyone's interested)
Washington - 1st in score thanks to a few wonders and abundant land; 3rd or 4th in military, behind in techs. Almost exclusively Jewish. Current 'enemy'. Only living civ with which I've had a military conflict.
Hiawatha - 2nd in score, he has a ton of wonders, substantial land, and unfortunately beat me to the Sistine Chapel. Mixed Hindu (founder) and Jewish. My steadfast ally.
Me - 3rd in score. Entirely Jewish (founder). I still generate massive amounts of faith thanks to completing Piety, and have far and away the largest cultural output due to World Church and my religion, Judaism dominating the entire west. I'm also positive I have the biggest tech output, and currently have the largest economy (just recently passed Washington) and the 2nd most powerful military, as well as the tech lead (61% vs average of 54%). After a spite of unhappiness following my recent war, I have returned to happiness and population growth (demographics put me as the 2nd highest population).
Ramkhamhaeng - 4th in score, probably because he hasn't completed many wonders. Former tech leader. Almost entirely Buddhist (founder). Current 'enemy', historical 'ally.'
Pacal - 5th. Almost entirely Christian (founder). Former tech leader, along with Ram. Current 'ally'.
Alexander - 6th, his capital has 27 citizens so the demographics say he has the largest population. Almost entirely Shinto (founder). Current status unsure, historical ally, projected enemy.
Atilla - 7th. Mostly Buddhist. Current status unsure, historical 'enemy'. I'm subsidizing his war against Ram, but I originally bribed Ram to attack him (poor decision in retrospect).
William - 8th. Entirely Jewish. Current status unsure, historical and projected enemy.
Augustus - 9th. Mostly Jewish, but founder of Confucianism. Historical 'enemy,' projected enemy. Has been devastated by wars due to his position, but has held on to the Songhai city he took early.
Askia - 10th. Has been devastated by wars due to his central position on the map. Two cities currently held by enemies. Historical 'ally.'
Harun ar-Rashid - 11th. Mostly Jewish. Historical and current 'enemy.' Has only one city left due to protracted war with many enemies, particularly Atilla.
For example, in my current Ethiopia game (King, yeah I'm still building up my skills) I set up an early alliance with Hiawatha and Augustus against Askia. As soon as I saw Rome expanding too much, taking Jenne from Askia, I shifted to ally with Askia after his denunciation wore off, though I kept my DOF with Augustus temporarily and kept exporting resources to him for large payments per turn. I chose not to renew my alliance with Rome, and it broke down.
I later shifted towards building a coalition against Washington. I was aiming for a cultural victory (I've abandoned this goal in favor of science or Diplomacy at this point, though I completed Piety

I've just finished my war with Washington as of ten or so turns ago, and successfully took two cities from him and puppeted them, as well as knocked him out of 2nd place in the military rankings; but there is a diplomatic revolution in the making. A while ago, I bribed Ram (72 gold and 2 Horses!) to go after Pacal (the tech leader) but strangely Pacal denounced William (a longstanding enemy of the Iroquois-Ethiopian alliance) and DOFd with me and Hiawatha. Logically, I predicted that this would produce a rift, now the seeds I sowed for temporary gain are beginning to sprout. I later bribed Ram to go after Atilla (a semi-free agent who turned against our alliance but is apparently friendly with me now) as Atilla completely took over Arabia except for one city (they were basically a pariah at one point).
Now Ram has seized the previously Hunnish Mecca as well as swallowed one of my city-state friends. He's fourth in the rankings but I expect him to quickly move up. Greece also turned down a DOF, so I checked the Diplomacy screen and saw that Ram had denounced Hiawatha, so I backstabbed him and got an angry response from Alexander. I'm still friends with him, and he's still at war with Washington, but who knows how long that will last?
Anyways, a general overview of my current situation (if anyone's interested)
Washington - 1st in score thanks to a few wonders and abundant land; 3rd or 4th in military, behind in techs. Almost exclusively Jewish. Current 'enemy'. Only living civ with which I've had a military conflict.
Hiawatha - 2nd in score, he has a ton of wonders, substantial land, and unfortunately beat me to the Sistine Chapel. Mixed Hindu (founder) and Jewish. My steadfast ally.
Me - 3rd in score. Entirely Jewish (founder). I still generate massive amounts of faith thanks to completing Piety, and have far and away the largest cultural output due to World Church and my religion, Judaism dominating the entire west. I'm also positive I have the biggest tech output, and currently have the largest economy (just recently passed Washington) and the 2nd most powerful military, as well as the tech lead (61% vs average of 54%). After a spite of unhappiness following my recent war, I have returned to happiness and population growth (demographics put me as the 2nd highest population).
Ramkhamhaeng - 4th in score, probably because he hasn't completed many wonders. Former tech leader. Almost entirely Buddhist (founder). Current 'enemy', historical 'ally.'
Pacal - 5th. Almost entirely Christian (founder). Former tech leader, along with Ram. Current 'ally'.
Alexander - 6th, his capital has 27 citizens so the demographics say he has the largest population. Almost entirely Shinto (founder). Current status unsure, historical ally, projected enemy.
Atilla - 7th. Mostly Buddhist. Current status unsure, historical 'enemy'. I'm subsidizing his war against Ram, but I originally bribed Ram to attack him (poor decision in retrospect).
William - 8th. Entirely Jewish. Current status unsure, historical and projected enemy.
Augustus - 9th. Mostly Jewish, but founder of Confucianism. Historical 'enemy,' projected enemy. Has been devastated by wars due to his position, but has held on to the Songhai city he took early.
Askia - 10th. Has been devastated by wars due to his central position on the map. Two cities currently held by enemies. Historical 'ally.'
Harun ar-Rashid - 11th. Mostly Jewish. Historical and current 'enemy.' Has only one city left due to protracted war with many enemies, particularly Atilla.