What a great article, very interesting. It's very intuitive to focus on astronomical scale characteristics of planetary systems, but I think smaller scale characteristics might have a surprisingly outsize impact on the amount of life a planet can sustain. Like, for example, atmospheric currents above which land masses happen to fall under might be an underappreciated factor, because atmospheric currents help determine amount of average annual rainfall, which is the limiting factor to biodiversity per square kilometer in tropical rain forests (not sunlight, or heat, or- though this is more debatable- nutrient availability), the earth biome with the highest count of it. On Earth, it's the difference between the Sahara desert and the Amazon rainforest. One lies about 30 degrees latitude north where downward flowing cold air creates a high pressure zone between the Hadley and Ferrel cells with such little rainfall it becomes a desert, while one lies 0 degrees latitude where upward flowing warm air creates such huge amounts of rainfall, it's enough to sustain the biodiversity of a rainforest.