I'm just wondering if anyone ever actually got Darius (1 VP per black city card) to work really well in a 3 player game.
1) There's only 9 black city cards in a 3 player game, just as bad as Varro (1 VP per yellow), except Darius costs more with no chaining.
2) Black city cards are actually more like a 2nd/support color, much like yellow. They expand the reach of nearly every fundamental 7 wonder strategy.
3) Black city cards don't usually have synergy with itself. They cost coins or were behind in VP efficiency in the first place.
The thing is that actively drafting this color doesn't actually disrupt other strategies whatsoever, especially leaders with multiple colors like Justinian and Plato.
The cards themselves have two clear resource patterns: Wood+Ore+Loom/Glass and Brick+Stone+Glass+Papyrus with a few exceptions.
Basically one pattern goes for military + debt, while the other goes for diplomacy + military debt. The masks and VP cards are split 2/3 and 1/3 in synergy.
However, even if one actually gathers the necessary resources, usually the black city cards themselves are not the optimal pick, especially in attempts to draft large quantities solely for VP.
To have Darius worthwhile as a leader, you need literally 6 of the 9 black cards.
My playgroup concluded that you literally need to run Darius with Diocletian or Caligula to even consider the black city strategy. Even then, you still might not want to recruit Darius in the third age.
I feel like the sweet spot on picking black city cards in a 3 player game is more like 2 to 4 picks, and that's only if it actually bolsters your strategy. Most of the time you actually need such cards to be dropped on you after you already drafted your key picks.
What kind of approach do you use with Darius in a 3 player game?