To make this card more viable:
Change from:
+Ship 2 Envoys
+Allows Envoys to build trading post and construct military production buildings.
Change to:
+Ship 2 Envoys
+Allows Envoys to build trading post and construct military production buildings.
+Allows Explorer to train Envoys
+Increase Envoy limit to 10 (normally 5)
I think it might be cool to make envoys a useful combat unit for Dutch, they can soak up a lot of damage in age 2 and age 3 fights. The difficult thing about them now is that it is cumbersome to replace them mid fight as the limit of 5 means you have to wait for all of them to die to begin replacing them, in addition to stopping villager production to replace the envoys.
I agree with making Envoys more useful with that shipment, however I’d steer away from them being useful in direct combat, as an Envoy historically is not a combatant, rather a peaceful tool - a diplomatic unit. Maybe once that shipments out, the more Envoys you have trained (using your new build limit) and have out anywhere on the map, the larger the build limit of any native/minor civs units you are allied with.