Not talking about the article quality (obviously lacking as it has been previously commented), but the features themselves
10/10 We love the king day
- While, as commented by @bbbt
wltk day (and revolting cities) are in the game as the positive/negative amenities boost, maybe some specific event stating some cities celebrate or are against your rule would be nice for flavour. It can't be something that triggers very often (so it should be at the amenities extremes, or depend on more topics), and it does not need to have any specific bonuses (maybe quest-triggering, if quests were a thing, or allowing you to build specific versions of buildings). The boost is good as it is with the current amenities rule.
- Agreeing spionage/visibility game may need rework. Civ IV BtS intel management was the most enjoyable for me, and it could be mixed with diplomats. Make it integrate with religion so religion is not that one-dimensional (Apostles/Missionaries may also work as diplomats... somehow and depending on the circumstances) and maybe with culture (who says Rock Bands cannot spy or spread propaganda as well
). Really, creating a "civil" unit layer were all these kind of units (plus bards/troubadors, merchants, scholars,...) interact might work in interesting ways.
08/10 Unique great people
- Not that fan of unique great people for civs. I prefer unique great people as currently, maybe with a "bonus" for certain civs to get their great people (e.g. England needing half g.p.p to get Newton, or Rome-Italy needing less points to get renaissance artists, if it can be properly balanced). But if you build a "civil" layer like explained in 09/10 there might be quite a lot of room for Unique civil units.
- Saying the "strenght" of Civ were scenarios says much of the article quality, IMHO... the strenght of Civ is the main game and scenarios are just fine as long as they do not detract from the main game development.
The concept of spending population to rush buildings does not fit that well with Civ5-6 model of buy-or-build (but not rush in the middle of production). As with other topic, you can consider it is still present if you allocate population to production generation disregarding food, in example. Some "dark" policy increasing greatly production at the cost of other yields might be nice, but slavery for the sake of it, as it has been commented is such a controversial topic that does not need to be brought to the table, as it is still well simulated by specific game mechanics/decitios.
0 Attack and defense values. As said in the initial post, with bonuses to attack/defense for some units this is more or less available already. Would be just cosmetic splitting the stats and I don't think would make things really easier.
04/10 Puppeting a Conquered city
- I'd say yes, and it really does not need to involve anything more than letting the city to be AI-controlled: the best thing is to avoid the micro-management of cities that, on the other hand, are just buffer space between your core and your enemies. If that comes with different loyalty challenges/rules (maybe less impact of foreign loyalty pressure, but at the same time, less spread of loyalty to your empire) it could be an interesting twist. Puppet cities should not count towards district cost inflation also, in example.
I liked health mechanics in Civ 4 and how they . Habitation in Civ6 tries to model that but I think fails to consider many positives and downsides and has no major negative impact: plague could be one. I think health is something that could be extended and have different ramifications, not only in the part of plague, but also in the diplomatic/cultural game and overall victory conditions.
. As with puppets, as a way of making domination game less cumbersome, is something to be considered. I think it has been pointed out as well (maybe not in this topic) but bringing civil war mechanics where part of an enemy empire surrenders and other stand against you (specially if same-civ or similar-civ leaders are available), is something that could be interesting.
01/10 National wonders.
I would not reintroduce national wonders per-se. They might not be even fitting with current wonder-in-tiles system. But if number of major wonders increase, impact of the last ones to be build could be decreased to work akin to national wonders. And it might be interesting as well to have "supercharged" districts functioning as some of the Civ V national wonders (so your civ could have its main campus, its main CH, etc... providing increased benefits to that of an standard district).