Wanted to share some observations from an Argentine run to 1920 AD (based on Regent/Normal, 1700AD start). This is based on last Sunday's update. I'll put in some thoughts on my Argentina playthrough in the Suggestions thread.
As per usual, the Western Euros have run away with the game. Britain in particular I can't really understand how they are so strong --- they barely have an empire here! Germany too was neck-and-neck while the USA and Japan (who by this time should be pulling up, historically) are reasonably behind (and as a South American player, I am in the relative stone age). As Argentina, I didn't interfere enormously in global affairs; just interdicted a lot of boats at the Strait of Magellan and threw outdated units at Spain's South American holdings.
My thoughts are that maybe the Global Era technologies (and maybe also the late Industrial Era technologies) could use some tech cost increases. Whenever I play a powerhouse civ and reach that era, I am researching each tech in 1 to 3 turns at most, and I assume the AIs are in a similar bucket. It also makes the really strong Science wonders that show up in the Global Era (CERN, Atomium, Oriental Pearl Tower, etc.) feel really pointless because by then you don't even need those wonders to pump out techs in no time at all.
Also, as a broader mechanical change, perhaps the tech spread mechanic can be drastically buffed in the Industrial Era onwards? It can feel very hopeless as a not!tech-leader civ to play the game and never even think of approaching the tech realm of the leaders while they just speed away building Global Era wonders every other turn.
Here's some screenshots. I also attached some saves below.