I've finished about 80% of my games. I could probably continue them maybe, but I'm currently doing a marathon game to determine whether it's more difficult than quick (doesn't look like it so far 400 turns in, which is still mid-game) and when the AI secure their victories. On quick, the AI gets their victory wonder at around the halfway mark of around T170. On standard it's around T260-280. On epic, it's around T350.
Of all games, the most common strategy is to take out the harmony players first because of their easy victory condition. Game becomes difficult when there is a harmony runaway faction, which gets worse as they spam solar collectors all over their empire. The only exception is if some faction, harmony or not, is aiming for contact victory. Once those factions are down, you can win at any time, although I'd probably target the supremacy factions next. I'm yet to see whether AI knows how to send troops into emancipation gate, let alone build it.
You're in luck. The devs said they are modifying the 4 civs you haven't played in the patch.
Which ones? I reckon the following need some additional bonuses or changes:
- African Union -- change 10% to 25% food when healthy.
- Slavs -- maybe instead of free tech from first satellite it could be a tech boost for each different type of satellite you send into orbit.
- ARC -- +1 spy along with more effective spies.
- Brazilia -- +50% XP and all units gain an additional maximum level, the 10% combat bonus could be changed to all units start with +10XP.
Remember the time we thought Firaxis was going to put upsides and downsides to sponsors? They could revive that idea, make the existing UA's more effective and add downsides.