I am fairly sure they've begun development of Civ VII by now--at least in the rough stages, simply based on practicality. Civ games take ages to make, yes, but I don't think this is a case where Firaxis is going to have the entire team working on an expansion (or even multiple expansions). So the idea that Civ VII would be that much further away and that Civ VI therefore ought to get a third expansion just doesn't ring true. Regardless of how many expansions Civ VI gets, Civ VII will take years to develop, so I don't see how a third expansion necessarily helps or hinders on satisfaction level there.
There would be another problem with a third expansion--feature bloat. Once we have too many features (let alone civs), they will be hard to differentiate. Golden ages, governments, and world congress will all give bonuses, but simply packaging new features (like corporations) as new clusters of bonuses won't be fulfilling. Disasters are already in the game even if diseases aren't. Vassalage might be interesting, but not as such for players to be vassals, surely.
But the main problem is I don't see what kind of cohesive theme a third Civ VI expansion could have.
Adding new civs is easy enough, but an expansion is more than just a series of new civs...unless we want to descend to the level of the (generally lower quality) extra expansions Microsoft has given Age of Empires II (The Conquerors was the only truly good expansion IMO, despite some good features and interesting civs in later expansions)
And frankly I do not have interest in two more expansions. One more, sure, based on the cohesive theme and features of GS. But two? Unnecessary.
You're making a lot of good points. I agree with you, Civ VII must be in the early stages of its development by now and you're right, by splitting teams, getting expansions for VI while preparing VII is not contradictory in itself.
I also agree that nobody wants low quality content just to have content... It's worse than not having anything, it'd be detrimental to the game. When I think expansion for civ games, though, I don't think the game could get bloated with features. If they were to release 4 more expansions I could see that happening, but it won't be the case and I really think of a 3rd and hopefully a 4th expansion as ways to wrap up the game, to make it feel complete, infinitely replayable and enjoyable.
Now, these expansion will not have to focus necessarily on tons of new civs and features but rather on a few, well implemented and deep mechanics (and improvement to the AI along the way) that would really make Civ 6 great at what it is meant to be according to the developpers that is:
- creating a living map
- and making the player have to make choices at every turn.
It is only my opinion but it seems to me that Civ 6 after Rise and Fall has a lot of unexplored potential in this regard, and I don't see how Gathering Storm by itself will be able to maximize it. It would still take, to me, 2 more expansions after that to reach that state. However, as you said, these expansions have to be conceived with a purpose in mind and not just be content for the sake of content.
I feel that GS is going in the right direction somehow, and I would like to see the game being taken a few steps further, as it still has work to do also, in my mind, to recapture the true meaning of the "just one more turn" and "what will your civilization stand for?" original slogans that were the true motors and reasons for being of the game in the beginning.
Civ 6 could be great with a good two more years of development with those points in mind in order for it to become the bridge between the previous era of Civ, from 1 to 5, and a new era of civ, a meta civ era if you will, meta meaning that it would take civ in a new direction and at the same time be a great representative of what the franchise has always stood for.
To sum up, beyond the Sword and Brave New World made me crave for more and both times the following new game came out, it was a let down because it felt like we had to start all over again while these games could still have been improved. It feels even more true in the case of VI, which I believe would need 2 more expansions after GS to feel complete under the condition that it is not content for the sake of content as you rightfully pointed out