Bandeirantes exploration bonus
1) We obviously have to nerf the value on the exploration because its wildly overbudget for a UU
2) Because it comes in late medieval, you are incentivised not to explore before that.
I think that's a bit pathological, but more seriously the AI doesn't do it.
3) The bonus is "tall", it gets diluted by having more Cities. But Brazil's kit was intended to be a sort of "wide" cultural victory.
Simultaneously, we have Portugal. It has the "Age of Discovery" promo on University of Coimbra which has similar issues
Yet, getting big payoff from exploring the map is quite fun and provides variety. Meanwhile Portugal has a "more TR is better" UA, just like Venice, Morocco, and Ottomans.
It's also called Mare Clausum, but I'm not sure it really captures this idea.
To me, the Age of Discovery is this big Portuguese moment, if any civ has this "explore the world" mechanic it should be them!
So, if we moved the exploration-gives-yields effect to the Portuguese UA, we could kill two birds with one stone
1) The value can stay high (and fun) because it now has UA weighting
2) We can have it unlock early (and even scale in time)
3) And a third bird: Portugal is also a more natural "tall" civ, and so there is a natural gameplay reason for them to have this bonus over Brazil
UA: Padrão Real
After discovering Sailing, Naval and Recon units gain Gold, Science, Culture, and Great Admiral Points when discovering tiles, scaling with the discovery of Compass and Navigation.
We can start with a value of 1 (current Brazil value is 3) that doesn't unlock until Classical so the very-early game is not affected. Then at Compass it goes up to 2, which is 50% less than current Brazil value, then reaching the Brazil value at Navigation. This is similar to having Era Scaling.
This way, University of Coimbra would lose its promo. Here I would add a new one
Promo: Mare Clausum (for all Cargo Ships)
Gain Naval Units within 4 tiles heal 15 HP if they kill an enemy, and gain 25% CS outside of friendly territory
Uses all existing columns:
VisibilityChange
IsNearbyPromotion
NearbyRange
GiveDomain
GiveOutsideFriendlyLandsModifier
GiveHPHealedIfEnemyKilled
This is nice because it does the Armadas da India without using the word Armada
Then we use TRVisionBoost on the UNW to give 4 Sight to Cargo Ships (currently 0 sight base)
With 4 Vision, if you send the Cargo Ship to a distant city you can reveal lots of tiles and trigger the UA, which affects them as Naval Units.
This is a way of having a sort of Unique Cargo Ship without the associate art weirdness and the fact the Nau is already in use.
I would also add some more yields to the University of Coimbra theming bonus (was missing in first alpha... whoops!)
because as I understand it the Cursus conimbricenses, and the cultivation of important literary and scientific texts like the first edition of Os Lusíadas are the main claims to fame.
The bonus gold to Universities is also a little off, since for a long time it was the only university in all Portugal, so instead I would give a bonus to buildings that must be purchased with faith, reflecting the centuries of Jesuit scholarship.
Back to the Bandeirantes. These guys went into the Amazon and colonized it.
I suggest something like UnitPromotions_YieldFromBarbarianKills to give Gold, Production, and Border Growth to their origin city. They can also get Influence with nearby CS on kill, allowing you to make friends and allies even far away.
This supports the Brazillian mission of colonizing unclaimed inhospitable territory, often in the new world and on island, that will naturally be filled with barbs that must be cleared.