I've always found it a bit odd, that in Colonization, The King would raise the tax rate to the point when selling goods to Europe makes no sense.
In real life, Europe wanted its colonies to buy european-made goods, for revenue and to keep the them subdued and dependent without industry of their own. The Tea Party was primarily about refusing to buy tea from UK to show dispproval for the British colonial tax policy.
The Stamp act was a duty levied on every legal document. A purely bureocratic fee.
Hence my idea;
Instead of tax rate automatically applied to sales of ll goods, lets make the King add mandatory fee to production, education etc. A sum of money, which the player must pay to complete education of a colonist*, commision a ship, finish a colony improvement etc. Each consecutive stamp acts would raise that sum even higher, angering the player... and that's the whole point.
*Having to pay to finish eductin is a part of C4C gameplay, and it is annoying.
Not a bad idea. We have already implemented upkeep, so this should not be much of a problem.