Very happy with what I'm seeing here. The coastal city buffs were much needed, I love the look of the new maps, and I love the improvements to—well, improvements. I like how a lot of them are based in scaling the improvements through tech unlocks; one big complaint I have with Civ VI is how I feel that a lot of the techs in the game sort of don't really do a lot (looking at you, Astronomy). A major reason why this problem exists is due to the splitting of the tech & civic tree (I change I think is overall super beneficial to the game), and requires a lot of the unlocks to be split between more checkpoints. But just giving more techs a simple +1 production or something to a certain improvement makes the game's progression much more exciting. I'd still like to see a lot of the game's techs that don't offer much (such as Printing, Astronomy, Mathematics, Buttress) to give more unlocks to make them more worthwhile teching.
I'm a bit surprised to not see any Civ-specific balance changes in this announcement. I hope there will be at least some Civ buffs in the full patch notes, because Civs like the Khmer, England, France, Mapuche, Georgia, Egypt, and Spain could still use some love. (Also, this is totally off-topic, but does it bug anyone else that Arabia doesn't have a desert start-bias? I mean, the Civ is probably stronger without it, but I want my immersion dammit!)
My biggest problem still standing with Civ VI is that I still think the unit tree is whack. I don't like how there's no unit between Swordsmen & Musketmen, and Musketmen & Infantry. The same goes for Catapults & Bombards lacking Trebuchets and some sort of industrial artillery. I don't like how useless anti-cavalry units feel because Melee units just decimate them; it's a bit of a problem that cavalry units' best counter is cavalry units themselves. And the naval unit progression is just an absolute disaster. This is one area of the game that Civ V just did so much better than VI, which is a shame, considering how great the changes to the promotion tree and combat itself are. Adding more units, of course, means spending more money on upgrades, but slightly reducing upgrade costs will help offset their increased rate of upgrading.
I also dislike how barren the actual city center itself feels. It just seems like the city center gives you only a few buildings in the ancient era, then walls, sewers in the Industrial Era, maybe Flood Barriers, and absolutely nothing else. I'd like to see the return of buildings like the Caravansary, Courthouse, the Police Station, Windmill, Hospital, Recycling Center (heck, even the Spaceship Factory as an extra building in the Spaceport to make that district more interesting, though that's off my original topic). Just anything to make that district feel less barren, because while I adore districts as a concept, they make the actual city itself feel irrelevant.
I don't expect any of those changes I just mentioned to be seriously addressed in the next patch, but hey, I know they've somewhat teased another expansion coming up, so maybe then they'll make those additions. I think a few minor problems hold Civ VI from fully realizing it's potential from being the clear best game in the series, and while the devs have gone on to fix a lot of those problems in the past few patches, I think fixing the unit tree is the biggest one, while making the city center feel less barren and making techs more interesting are a second & distant third priority.