I'm happy with trade routes. They change the game in one of the most innovative ways I've seen in the Civ series. It might require a few tweaks here or there, but I want to keep trade in its unmodded state for a while.
Something important is we can only send 1 route from a source to destination (Washington to Paris), but can funnel multiple sources to one destination (Washington and NYC to Paris). It's sometimes more effective to split up our routes in the early game when distance and city count limit our options. I think we only
need to cluster trade routes in a single city is if we have powerful buildings in a city like the East India Company or Colossus. Otherwise, we can just build an extra Carav/Harbor or two. This can also have a benefit if we're trying to trade with someone out of range of our primary trade city.
Say we have 2 cities in the early game Washington and New York, and our possible trade destinations are:
5

2

- major civ city
5

2

- major civ city
2

- citystate
2

- citystate
If we can build 3 trade routes, and send 2 from Washington and one from New York, we get 15

6

This is more income than sending all 3 routes from Washington. Even if we have the Caravansary in Washington, splitting up our trade gives more science.
In addition, I believe trade adds to national income, not city income. The in-city tooltip shows trade below the line separating base income from total income, indicating it is not
not affected by % gold multipliers like the bank. I think it doesn't favor the capital or any other city.
I think the best approach to balance sea-vs-land trade for now is making land trade cheaper, but less profitable, so we want to switch over to sea trade once it becomes viable. The strategic decision is
when to make that transition. This is basically what it's like already in BWN. I just emphasized it a little more by making the Caravan and Caravansary slightly less expensive.
@mystikx21
I agree the unmodded caravansary feels underwhelming with its high up-front cost and rare usefulness. We might build one per game, but I usually just skipped it and upgraded to sea routes. I'm really happy with the exotic food bonus on it (citrus, truffles, banana). I was trying to find a home for those resources for a year. They don't really fit anywhere, so the caravansary works great, giving the building situational value when we've got those resources nearby. Reduced cost also makes it much more competitive versus the Harbor.
@albie_123
Ancient ruins are the same abundance I've always seen. I think you just had a random lucky map. I see AIs clear barb camps about as often as before. I haven't noticed changes there, but I rarely see the camps in opposing territory anyway. Tenets are simply a different name for policies, the same thing with a different interface. AIs were more capable at capturing cities in Gem than BND due to a few adjustments I made to combat. Those improvements will return for Cep Basic.
In one of my games, I found it helpful to create an island city near another continent to trade with the leaders on that continent, because my original trade port couldn't reach that far. This is one of the few times I've had two trade cities operating simultaneously.
@xInVicTuSx
The effect ideologies have on each other depends on your current influence over the leader. This depends on your ratio of tourism to culture. If you have a strong culture, strong tourism, or both, you can make everyone else in the world very unhappy. The same also applies in reverse. It's so late in the game I haven't had much experience with it yet, so I'm going to leave it unmodded for a while.
Can we introduce a factor that inversely influences the gold bonus of trade routes? Like the more routes you have, the less it gives?
If I understand you right, this already happens because we exhaust the best trade options, and must send routes to less-rewarding destinations.