Want to mention now something for balance and not technically.

The happiness system is still a bit weird for me and heres something I didnt really understand. As example, my capital have a size of 46, a total happiness of 43 and unhappiness of 17.
The interface for empire wide unhappiness shows me, that I have 1 unhappiness, but nothing is listed below the unhappiness standard sentence. It probably comes from WW, cause I have 1 WW unhappiness in my capital, but the war is long ago, 43 turns.
It also seems the maximum unhappiness of my capital is 17, cause I have 1 unhappiness by WW, 14 by specialists and 2 by distress, distress says, it goes up to 2 unhappiness and all other yield based unhappiness is capped at 0.
An other city has unhappiness caps of 0/1/1/3, and this way I get only 5 instead of 21 unhappiness. Is this really intended?
This makes Public Works really senseless, cause it wouldnt reduce any unhappiness, the caps are always smaller than my potential unhappiness. I also want to mention, that spending 1k production in an industrial age city to reduce the needs from 250% to 240% is in no relation to the cost you have to pay. High unhappiness occurs in cities with bad infrastructure, but why should you invest such amounts of hammers to reduce only a "relative" small amount of the modifier, if you can also build infrastructure which help with unhappiness AND generate benefits?
Second point:
I like to use internal trade routes to push infrastructure and size of my cities. So I was very happy to see internal trade routes buffed with those instant yields from buildings. But I have to say honestly, those yields are TOO HUGE.
Even with a 25% buff from statecraft you are able to generate only 20 production per turn with an internal trade route in modern era. If you finish it, you get 750 production, within 25 turns, thats 30 production per turn.
You get close the same amount of yields by ITR as you get by the ottoman UA. (500 food + 750 production VS. 750 gold + 750 culture)
Those ITR modifiers feel really awful, if buildings you will probably build anyway, give you an yield increase of +100-150% VS. policies which give +25-33% or a level 3 tenet with +200%.
I would take away the instant yields and simply increase the base yields by 25-40%. I think Gazebo will say, this could make ITR too strong in combination with trade route modifiers, especially Order tenet. But keep in mind how late the strong modifiers (Protectionismn, Iron Curtain) come, and which impact they will have that late in the game.
EDIT: Very strange AI behavior: I entered atomic era and immidiatly got 5 denouncements from 6 AIs (the 6th is my vassal). Even my all time friend denounced me, we had short before a defensive pact and never any conflict.