I've watched City States spawn a warrior every two turns at the beginning of the game, and have bigger armies than the surrounding regular Civilizations in the first 20 - 30 turns. But then, I've also seen Barbarian Camps spawn a new Horseman or Horse Archer every 2 - 3 turns, literally faster than you can kill them off. If this is the only way the developers could think of to make those elements of the game competitive, then defenestration is too good for them - they should be tossed out the nearest Windows 10.
Of course, on the other side of the coin, along about the later Medieval Era the City States are still spawning warriors, an occasional spearman, and archers, so the 'carpet' becomes a Carpet of Targets for crossbowmen and knights to stomp on.
Neither situation makes for a competitive game, but, frankly, compared to the problems with the Tech Tree pacing, unit (non) upgrades, Gold versus Research versus Growth problems and botched UI and AI, what's a little spawn problem?
