As a counterpoint, the research bonus is always active; it's something you get from turn 1 no matter what, whereas the yield bonuses such as Financial's need both time and investment to kick in. +1 research to scientists or a bonus to tech transfer aren't out of question, though.
Yeah, that is true. In particularly in RI, the +1 commerce from FIN is (thankfully!) harder to activate than in vanilla, so you'll either have to get a couple cottages and work them, have some plantation resources or get the colossus (it's insanely good for FIN).
I tried a casual random map game with switchable leaders until late classical as Dravidia, and 1 turn before the middle ages I saved so I could go for the financial, humanist and progressive leader each after the tech completion. (I think it might be the only civ that has all 3 of these traits separate without a counteracting negative trait on those leaders, e.g. isolationist.) Also deliberately did not go for colossus since it'd skew the results.
I did not build for any particular strategy and at this point had basically no hamlets or villages, just casually cruising along unfocused.
None of those traits: 402 research/turn
Progressive: 414 research/turn
Financial and humanist: both 425 research/turn
(All at 100% research spending for the comparison, every other fraction favours the non-progressive results in comparison)
This definitely raised my opinion of humanist, since it works from turn 1 and outperforms progressive and can for the early game keep up with financial, but I also know that had I played for the financial trait from the start I'd have a lot more money tiles and probably more income as well.
- Magna Carta is gone; Himeji Castle elevated to a Monarchy-dependent World Wonder status. Removes upkeep for vassal cities (for those who - due to it not being documented anywhere - don't know the vanilla vassal mechanic, master's number of cities upkeep increases as if half of vassals' cities was theirs), doubles military production for vassals.
Will Himeji castle be disabled in "no vassal state" games?
Also, while the heraldic chamber was a meme and won't be missed, I personally will definitely miss the fortified keeps and constables! I personally really liked how the feudal aristocracy gets a few small buffs as you progress through the middle ages, and I can attest that I've once gone for feudal aristocracy + monarchy specifically for fortified keeps and feudal land tenure, as I was in a really tough war with my neighbour and needed all the city defence I could get. In general I really like those double-civic national buildings, like feudal land tenure and enlightened absolutism.
Although, now with constitutional monarchy, there really is no point for a mid-late game autocracy at all. (I thought that the distinction between "autocracy" and "monarchy" was that already, that "autocracy" is an absolute monarchy while "monarchy" is more a constitutional monarchy.)