I did a TONNE of maths on this before it got released. I was enjoying the Brazil revolution before anyone posted it on the forums. I mained Portugal since TWC and went back to it after they wrecked the Ranger play on Britain for the Cassadores.
Age 1, Feitorias is roughly equal to 2 and a bit vils.
Age 2, it’s equal to around less than 4. (2 TC’s, but market upgrades making vils more effective reduces the comparison down a bit.) (Germany for example gets a 4 vil card in age 1 (settler wagons) already and nobody’s panicking.)
Age 3, it’s equal to maybe 5 vils. Give or take.
Is it a good card? Yes. But it takes until Age 3 before it starts to be better than the original 3 vils another civ could call in. Kinda.
Is it OP if you send Donatarios and the 1 TC wagon and the 2 TC wagon, then go imperial and do it all again? In my opinion, no. Let’s compare it to factories instead from this point forwards.
Fully upgraded factory: 7.15 resources/s
Portuguese TC: 1.5 resources/s
(0.6 Food, 0.3 Wood, 0.3 Coin, 0.3 XP)
1 factory is better than 4 TC’s for resource production and can also make heavy cannons with engineering school on Portugal which is excellent. 1 factory is significantly better as it can be configured to produce wood exclusively, which if you rejig your economy around it, actually puts that factory as equivalent to about 5 and a half TC’s.
To actually HAVE 12 TC’s (the theoretical maximum (Portugal doesn’t get a free covered wagon for Imperial age)) you have to spend 1,000 wood and FIVE shipments, two of which MUST be done before imperial delaying that uptime and two of which cannot be sent until after. This is theoretically possible. This is not practically possible in a game where someone is actually trying to kill you.
Sending all these cards nets you a lower villager pop economy though, right? So you can have more military units? Yes, sure. But you could have a better economy with the same villager pop if you send economic theory, refrigeration, royal mint, cigar roller and sustainable agriculture. You can also achieve this better economy earlier and without having to do silly games with your imperial time.
This is presuming you DON’T send these cards on a Feitoria build, as sending 10 econ cards is just utterly unreasonable, especially since half those cards only buff 2/3rds of your economy (the vils) while the other half only buff 1/3rd of it (the trickles).
Feitorias doesn’t hit the breakpoint of being unbalanced until you do a Brazil revolution where your opponent doesn’t counterattack you if they win the initial engagement. If this was the thing people wanted nerfed I could see the argument for it, although I really like this as it is and I’ll be pretty devastated if it gets removed as it’s not really PvP-viable anyway. At least not vs a competent opponent.
TLDR: Feitorias is weaker than comparable civs economic options, but insignificantly so. The card shouldn’t be included in a fishboom deck on Portugal for example and probably isn’t worth it if you can secure 4+ TP’s early game. However, it gives Portugal a viable option to play a land map without TP’s early for the first time in AoE3’s history.