Have you ever played Sid Meier's Colonisation? While it's sides variety is very much in line with "English: +25% Top hats 200% Tea consumption" rather than some thing more startling terrain is law. Buildings need wood, so if you want to build a dock on a timberless island you need to import it by boat. And good luck defending it when the motherland laughs at your independence.
Truly terrain is super critical to a bid to independence, without enough hills you'll be without high ground to hold or iron supply, yes you were a good little colony who made a lot of money, but your expanded too much and we're mot militaristic enough