Improvements of some cards related to natives:
Native Lore: On top of the current buffs, adds a passive experience income of X.XX/s for the rest of the game.
Native Treaties: In addition to its current benefits, it gives you a cart that can build a native embassy. Embassies give more experience when building them.
Note: In case you haven’t already allied with a tribe before this card arrives, it will give you the corresponding warriors once you build the trading post the first time you actually build the trading post.
Blood Brothers: In addition to the current benefits, the natives from the metropolis arrive faster and are also able to enable some of their improvements in your native embassy.
Note: In this case we will have to enable native cards as a shipment from the metropolis to civilizations that do not yet have them. We could also enable this card for civilizations that do not have it.
I think all this would help encourage the use of natives by other civilizations that do not specialize in using them.