Thanks for mentioning this bug! I've only used nukes once or twice, so I didn't know the maintenance formula was borked for them.
When I add natural disasters I want to select realistic ones: fires, floods, droughts, famines, disease, and so on. These are widespread, and major ones are likely to happen to a civilization. Each one also provides opportunities to improve society. For example, after the Great Fire in London, the city was rebuilt with improvements to fire safety, like wider streets and building with brick instead of wood.
In comparison, damage or death from meteors, meltdowns, tornadoes and such is extraordinarily rare. They get more attention on TV and movies because they're dramatic, but it feels immersion-breaking when they have a significant influence on games like Civ or SimCity. I've copied some of my findings below.
Cost of damage:
$362 billion : fires in the US in 2008
$1.8 billion : tornadoes in the US in 2008
$20.5 billion : total nuclear accidents worldwide 1952-2009
Lifetime odds of dying from:
1 in 5 : heart disease
1 in 7 : cancer
1 in 70 : falling down
1 in 100 : car crash
1 in 300 : firearm
1 in 500 : disease
1 in 900 : fire
1 in 15,000 : famine
1 in 30,000 : flood
1 in 60,000 : tornado
1 in 130,000 : earthquake
1 in 200,000 : asteroid
1 in 500,000 : tsunami
1 in 10,000,000 : nuclear