The changes are good, however, your impression about the industrialized part of the world is somewhat wrong. At that time, those countries who were industrialized highly treasured their superiority over other nations. They would not have exported their industrialized produce as much as sell it within their own country so as not to give other nations advantages over them.
I could be wrong there, but I believe that was the way things were. No opinion on colonies, because I'd only be biased as I don't start with any, and also am not sure how that issue was actually addressed. My only thoughts were that I believe colonies existed for the purpose of imports to the home country, while minimal "exports" would go back to the colonies. Colonies would be one possible beneficiary though if a country were to export industrialized goods. Interpret that as you'd wish though.
Hm, yes, perhaps you are right about that. I am trying to think then what incentive you would have, in game, to colonize/expand/conquer stuff if colonies would only drag down your trade balance, and therefore, your income. Unless, owning more colonies/land simply helped your income on a base level.
I am also not opposed to doing away with the "Trade Balance" category. I brought all of these stats over from where I found this but am definitely wanting to perfect and change things where need be. Instead, for instance, if you sign a trade agreement with someone in game, it could merely positively affect your income? Perhaps unevenly between the partners depending upon what is being traded between which nations, but still both positively?