If everything is a bonus, a bonus means nothing.
Every decission you make, every direction every promotion, dedication, inspiration, government, governor, amenity, legacy government, policy card, competition, pantheon, city state, wonder, building, improvement, Secret Society, alliance, unique hability, unique unit, adjacency... everything is a bonus. Even disasters give bonuses...
Why everything is a bonus? Maybe cause adding +1 in a line of code costs almost nothing.
The more they add to the game, the easier it is to see there is barely anything inspired, interesting or unique. The easier it is to see the flaws and the little care and effort fxs is putting in so many aspects of the game.