There were 27 civs, if I counted correctly, that received updates. Weren't there 50 civs to begin with and 2/3 were to be changed? Of them, the best changes are undoubtedly those to the Maya, Spain, Khmer, Canada, and Mapuche, and Georgia. These civs either had issues with their start biases or executing their abilities. The worst changes, to me, are split into two categories: ones that buffed already powerful civs (1) or barely impacted/nerfed mediocre ones (2).
In category 1, we have Korea and Inca. As of yesterday, I was convinced that Australia didn't need the coastal bias guarantee, but for a country like Australia, I can now understand it. Australia's problem was with Citadel of Civilization, anyway. Korea is now receiving extra science based on Seowon placement, which presumably was a bug (?) that should've originally been in the game. Extra science to Korea wasn't expected nor necessary, if the mine bonus wasn't working by design, just readjust the description to reflect this. Regarding Inca, they were already a very tall, production-heavy civ. I'm not sure what giving them more housing bonuses actually accomplished besides making them even stronger. You know what would have been a much better change to Inca? Making it so their UU wasn't a ranger replacement for whatever reason.
In category 2, we have Poland, Scotland, Netherlands, Zulu, and Sumeria. As if yesterday's stream wasn't bad enough, Poland's patch notes don't reflect the changes to the Winged Hussar at all; I suppose this is a mistake, but I'm a bit perplexed about where they went. I could write a whole thesis about why Poland's change is worthless and actually detrimental to them, but I would just encourage anyone who argues that Poland is in a good place to look at the new Khmer and tell me why Poland could ever expect to compete with them. Also, just consider, please, how Poland can actually now aid another civ in getting a religious victory through their culture bombs. On encampments, no less!
Scotland was just ignored for zero reason whatsoever. The community has been abundantly vocal about Scotland needing a change and this has been completely ignored. With amenities and happiness being updated in previous patches, it was only rational Scotland would be adjusted to these new numbers; why haven't they been? You don't need to play for that long to realize there's not many advantages to ecstatic cities, and Scotland's measly bonuses don't encourage the extra effort. Don't even get me started on how their other leader ability just doesn't exist at all.
Quick plug for Netherland's Radio Oranje. I don't mind the new changes. With an average of 15 trade routes, you're gaining 30 guaranteed culture from the ability, and it's worth remembering that culture is hard to come by at the beginning. I think it's still weak like Peter's Grand Embassy, but at least it's not that awful. I would just like to point out Radio Oranje was rated as the worst civ ability by this forum and probably did, therefore, deserve something much more than a simple +1.
Now to Zulu - the Ikanda changes don't erase the fact that Zulu's position in the game has been made much worse through the addition of new units. If you're conquering, gold shouldn't be a problem for the Zulu, but where did the science come from...? +1 isn't much at all. I would be interested in trying this ability out to see if you can do some conquest-science economy, but I just believe Zulu didn't really get what they deserved out of this.
Sumeria is a weird case, but I just don't fundamentally believe their changes were that significant. I'm still uncertain how this stacks (is it theoretically possible for Sumeria to get +20 combat strength against other units? I'm not really sure), but they didn't really address Sumeria's main problems. I think that's my biggest grievance about most of these changes, honestly. Sumeria really struggled because their abilities were lackluster and the civ itself was only good because of the UU and UI. Now, it has another 'bonus' plopped onto the ability, but the fundamental problems of Sumeria haven't really changed. Allies won't engage in much combat, so you're almost never going to get those pillage bonuses. A tribal village bonus from barbarians is so situational and will happen, what, 5 times throughout the game, whereas other civs (like Inca now) will be utilizing theirs all game long? Moreover, the tribal village reward is just a lottery ticket - not consistent at all!
Overall, I'm quite negative about what I've seen here, but mainly because our suggestions just haven't been listened to at all, and it's obvious now. If Scotland was changed, if Radio Oranje received something else, if Poland was just... not absolutely terrible, I would've been happy. But calling this the "biggest community update" was a disgrace when the community through the balance mods have done the changes much better. I'm sorry for my constant pining here lately, but when I instinctively scrolled down to Scotland and saw nothing... that was ridiculous. As I said yesterday, this was rushed and they needed to take another week or two to actually listen to us.
Edit: I completely forgot about Egypt being ignored. Consider them placed in category 2 for the same reason as explained with Scotland.