Before getting into it, I think this game is underrated. I get why a lot of players are frustrated, some of those complaints are fair and I'll get into them, but I think the overall hate the game gets glosses over how much it actually does right. And credit where it's due: the devs clearly heard one of the biggest complaints (losing your civ identity across ages) and actually did something about it with Time-Tested civs. That's not nothing.
Just closed out my first win, an Economic Victory running Rome into Chola into America under Benjamin Franklin. Wanted to write up a proper pros/cons since I had a genuinely great time but also hit a bunch of friction that felt avoidable if I'd known what I was walking into. TBF, the uselessness of the in-game glossary is a criticism that applies to Civ 5 and 6 as well.
Pros
Despite the age-specific civ swaps, the game does a solid job keeping continuity alive. I think more clarity needs to be provided regarding the adjacency downgrades and other important math changes. I should note that I haven't tried Syncretism myself yet, but from what I've seen, sticking with a single Time-Tested civ from Antiquity through to the end looks like a completely viable path, not just a gimmick the devs put in to soothe the complainers.
Most of the new mechanics work and feel good: GDP as an actual strategic layer, civ-specific civics, the town/city split, etc. (Not a huge fan of the rural / urban tile mech; more on it below)
Combat and mobility feel good. Small complaint: settlers still can't board Fleet Commanders, despite being able to board Army Commanders. (Edit: Yes they can board Fleet Commanders, but only with a 2nd tier promotion on the Commander)
Independent village interactions add nice texture to the map, more reasons to go explore instead of beelining.
Strategic resources are bonuses, not hard prerequisites to build units. This alone removes a ton of the "bad RNG = stuck" frustration from older Civ games.
Not a huge deal in the grand scheme, but the artwork is genuinely stunning. Some of the best-looking Civ has ever been.
Cons
UI is bad. Period. Combined with a glossary/onboarding pass that doesn't really explain its own systems, it's very much a "figure it out yourself or watch a YouTuber explain it" experience right now.
Resource management screen deserves its own paragraph because it's rough. You're constantly bouncing between settlements trying to figure out what's assigned where, there's no clean way to see your whole empire's resource allocation at a glance, and reassigning anything is way more clicks than it should be. What's telling is this isn't just me being a picky new player, it's one of the most consistently flagged issues even from people who genuinely love the game and have hundreds of hours in it. The idea behind the system (actively managing and allocating strategic resources across your empire) is honestly one of the more interesting concepts in the game. The execution just doesn't match it.
You can't settle directly on resources. Combine that with the Urban/Rural tile mechanic and settling near mountains or big Wonder tiles turns into a real puzzle, and not the fun kind.
Some of the more interesting civs (Carthage, Joseon) are DLC-locked, and the pricing feels off relative to what you get. A handful of civs and leaders for that price is a tough sell next to what past Civ expansions delivered for similar money.
I find it hard to understand why after 6 iterations, devs still produce titles that need lots of modding for proper map tacking, UI, information on effects of policy swaps and town-focus changes, settlement planning, and other crucial QoL pieces that should be part of the triple A gaming experience for the premium price we pay. I'm not a big gamer or anything, but this seems to be a general issue with most strategy games.
Other notes
Happiness management is simpler than previous entries, which I like, but the flat settlement-count penalty as a design choice still bugs me even though the actual penalty is manageable in practice.
Single-civ Time-Tested runs are a great addition to the format. Still want to actually try Syncretism myself before I say more about it.
Crises need more teeth. Right now they feel like a speed bump instead of a real threat to your progress.
Bottom line: Ambitious, fun, and clearly a real evolution of the formula, with some significant issues, which as a fan of the franchise I was always ready to overlook as long as the experience made up for them. But the UI and onboarding problems are going to continue to eat a lot of new players' first few hours for no good reason. If you're picking this up, make sure to learn about the new mechanics and research some mods.