Now that the shiny has worn off a bit for me, I find myself much more critical of the experience with GS. Granted that my interest in Civ6 had already waned once but I was hoping that GS would revive it and inspire me to play it more often. And the beginning of the first game seemed to be heading in that direction. The new environmental effects are cool, the first handful of WC pop-ups were interesting, and the immersion level seemed to increase.
I voted 'need more time to evaluate' but I would certainly say nothing about this expansion is in any way game-changing. Mechanically it's probably less significant a shakeup than Rise & Fall, which itself I felt had less impact on the game experience than the subsequent patches.
Then again, I'd reached a point I was happy with in Civ VI and accepted it as a sandbox. I was looking forward to Gathering Storm for the flavour, and so far on that count it has been ... a partial success.
But as I played a few long nights, the same old criticism came back and my reasons for losing interest in the game returned. As others have commented, there is just no GAME here. It's still just a sandbox and everything just feels flat and incremental.
The circumstances of my specific game have thrown this into stark relief. I spent about the first 200 turns almost wholly at war, with no safe way to get settlers to new locations and falling far behind on science for too long. I latched onto diplomatic victory as my last best chance. People were getting rocketry while I was discovering how wonderful steam power is.
A hundred turns further in, and I'm close to diplo victory, I'll be the culture leader by the time culture victory is close enough to matter despite missing many wonders (and trying for several), and if I'd invested any effort in creating a spaceport I would probably be at least no. 2 in the space race as I received Carl Sagan from the Nobel Prize for Literature and Werner von Braun from natural engineer points (and grabbed him to prevent a space power from doing so). This is on Deity, after one of the slowest starts I've ever had in the game, in which I made multiple significant mistakes that set me back, and in which I'm playing very suboptimally (including going for more than half a dozen Wonders I failed to achieve).
Even when the AI has the tools to win it seems deliberately lethargic about using them to let the player catch up. It's possible I'll lose the session regardless - but if so that's because of mistakes that cost me two diplo points from aid emergencies and from not anticipating that the AIs would vote to strip a VP from me in what I'd planned to be the final Congress. Playing badly should result in the player losing because the game demands tight strategic play, not because they're being ambushed by new game mechanics whose implementation they can't be expected to anticipate on the first playthrough.
None of this is the expansion's fault - it's the way Civ VI already plays and why I consistently describe it, despite the enthusiasm for it here, as worse than both Civ V and Civ IV. Even when it's fun, it is not really a strategy game because "anything goes" is not a strategy.
The 'power' mechanic seems to have fallen flat (I haven't seen the need to actually provide 'power' to my cities so that whole 'decision' is lost).
I thought that may just be me not paying enough attention to its effects (again, who cares if you have a couple less production in a game that isn't interested in pushing you to play optimally? If I can get most of the way to Sydney Opera House and lose much of that production when I'm beaten to it without any clear downside, it simply doesn't matter).
Of course much of that stems from the AI not providing any push. It just spins it's wheels and pretends to be playing but I don't feel like I'm in any competition whatsoever (ie, not militarily or otherwise).
I've been impressed with a lot of what the AI now does on the way to the game's end point - wars and expansion now look somewhat plausible, you can imagine defined reasons for conflict and the AI interactions that emerge during the game - but you're right that it's all just passing the time and the AI doesn't have winning as an apparent goal. For some reason a lot of people hated the fact that Civ V AIs were coded to try and win and blamed a lot of seemingly (to me) unrelated issues on that, but Civ V had the most dynamic late game of any Civ game and the closest contests for victory I can recall in the series.
I REALLY wanted to get back into Civ6 and i was REALLY hoping that GS would be that missing part that makes the game fall into place. But in the end, it feels like it just added some additional subsystems to the mix without doing anything to really address the fundamental issue I've had with Civ6 all along...
This is how I see it: They've decided what they want Civ VI to be, and it's not the strategy game experience of its immediate predecessors. Civ VI has a large fanbase which likes this new direction, and the expansions are for the people who already like the game as it is. They seem to have no interest in bringing back older Civ players who want more of a challenge, unlike Civ V whose expansions actively reintroduced elements older players missed and generally increased the difficulty of the game over time. So a Civ VI expansion isn't a failure if it doesn't add anything that changes the core gameplay.