So I managed to test it with a new patch, King difficulty (that's the last difficulty I played pre-patch, so I wanted a direct comparison). I also wanted to give domination victory a spin.
First of all, roflstomping everyting with long range modern artillery with baloon support is quite fun.
The inane leader animations are pretty satisfying when they squirm and bitch as you wipe them out one by one like the retarded children they are.
I wasn't expecting any challenge, and there really wasn't any. While I was pumping out 200 science and culture per turn, the best that AI could do was around 50.
I'd actually say Domination victory is pretty fun, for what it is - a power trip about squashing bugs.
And the game managed to shit on my glorious feeling of godhead by bugging out, when I annihilated the penultimate opponent, I got a defeat by conquest screen.
I guess Saladin was right in his final words, it's not a "real victory" after all.
I noticed an improvement in the amount of districts the AI builds, especially the ones that started on my continent, but the civs on the other continent were very stunted.
Not sure if it's related to barbarians in some way, perhaps since I was quite effective at wiping them out they popped up on the other side of the world.
Though I noticed that no civs were wiped out prematurely by them, so maybe something got improved here.
All in all, the AI is still unable to get good adjacency out of its districts, and neither can it work with trade routes, which the human can abuse quite effectively with the right civics.
I had more success playing with diplomacy this time round. Despite going for a Domination victory, I managed to be BFF with Peter, who was with me until I wiped out three other civs,
sometimes even taking part in a joint war, though he wasn't a very active war ally. Then he just went from BFF from immediate denounce. fair enough.
Getting friendly with civs is quite tricky, I had to abuse making promises to get quite a sizeable bonus to relations (build a city or parade an army next to their border, promise to stop, then do so until a popup appears).
It even managed to offset warmonger penalties, which in my opinion are way too severe, even though I only declared Colonial Wars with lowest penalties possible, it made everyone denounce me on sight, effectivelly shutting down diplomacy.
There were no more lolrandom sneak attacks by friends, which is a mixed blessing cause I actually had to look around for a Casus Belli, which made for periods of boredom.
In the end, the whole world devolved into a mess with all Civs denouncing each other all the time. It's a shame, cause the game turned out to be every man for himself, whereas
a group effort by a couple of civs might actually give me some challenge.
I think the current system is still fucked, because the AI is much to reliant on its fixed agendas in determining who to be friendly with, and the resultant modifiers are way too high.
For example, making friends with China and Brazil is pretty much impossible unless you purposedly gimp yourself, because the guys will immediately throw a tantrum whenever you build a wonder or get a great person.
Same goes for Catherine, I tried to butter her up once our relations were still neutral, just to see if I could, but she quickly decided we can't be friends cause she doesn't have a city on my continent. Also, she was lagging behind in civics,
so I got a sizeable malus from different government types.
All in all, it's possible to "game" the system, but it feels like way too much bother for very little gain. I really hope an inevitable expansion gives a full revamp to the system, allowing for a real Diplomatic Victory with something like the UN from the previous games.