People keep saying this and I keep wondering what game it is they are playing and how to get it instead of the one I'm facing. In the Civ4 I played, honest stacks of doom were very rare outside of marathon games and/or high difficulties. IF one made an appearance and a stack of 30 units walked out of the fog of war right into the weakly defended belly of my empire, it truly was time to face a feeling of impending doom. In the Civ6 I played I faced this exact situation, 30 units jumped me (though carpets of doom are impossible to overlook, so of course I knew they were coming) when I had only 3 defensive units in place. I didn't even raise an eyebrow (or bother to call in reinforcements) and whittled away the entire enemy army with three crossbowmen and the two cities in the area, hardly ever taking damage. Is this the kind of strategic thinking you're referring to?