Hi I've two ideas:
1) To use the missile building as a tax building with several options with each 2 levels: (similar to the tax system in RSII but with different options)
level 1: Base level
level 2 options:
option 1 silver taxes; requires resource silver and precious metal mines. level 3 requires level 2 mines
effects: very high tax income, reduces population health (since mines aren't good for population health)
option 2 silver taxes; requires resource gold and precious metal mines. level 3 requires level 2 mines
effects: highest tax income, reduces population health (since mines aren't good for population health)
option 3 Land taxes; requires resource grain and level 2 farms. level 2 requires level 4 farms
effects: medium tax income, reduces population growth and happiness
option 4 Trade taxes; requires trading port or level 2 market level 3 requires level 2 port and level 4 market
low: low tax income, small reduction in population growth
2) to add a path choice/policy 'building'
level 1: path choice
level 2 options: To be decided, for example: Economic City, Fortified City OR Administrative, financial, military, open
I think idea 1 is quite clever. I've never been a fan of the city types described in type 2.
That said, I recommend making the idea 1 buildings interdependent with the economic development buildings of that type. That will encourage players to build the trees correctly.
You can easily create a new building with multiple conditions.
[new building] requires factions { abc, } and [condition 1] or [condition 2] or [condition 3] or [condition 4]
{
capability
{
trade_base_income_bonus bonus [leve] requires [condition A]
trade_base_income_bonus bonus [leve] requires [condition B]
trade_base_income_bonus bonus [leve] requires [condition C]
trade_base_income_bonus bonus [leve] requires [condition D]
}
I'm with Quinn in those matters