maybe towns could hook up resources and get some defense boni? because I had a town and I found sulphur under it, and another town had oil under it
here is maybe an Idea
Cottage: 5% defense bonus, 25% of bonus's normal yields,
Hamlet: 10% defense Bonus, 50% of bonus's normal yields, -1 commerce on resource
Village: 15% defense Bonus, 75% of bonus's normal yields, -2 commerce on resource
Town: 20% defense Bonus, 100% of bonus's normal yields, -3 commerce on resource
you would round down so that they don't get that powerful, also they should lose 1 commerce per levels starting at Hamlet level (because you are rounding down cottages wouldn't get much benefit anyways)
food for thought
PS I got the build a bunch of Triremes quest, I had the GL so I got the bonus option, could the +2 commerce for harbor apply to ALL of the harbor type buildings? and the Combat I option for Triremes be change to Combat I for all Wooden Ships?