Just wrapping up my third game now. First was Jose Rizal with Maya, Hawai'i and Mexico. Second was Isabella with Greece, Spain and Mexico. Current one is Friedrich, Oblique with Persia, Normans and Prussia.
Maya and Hawai'i are both extremely powerful. Lots of their target yield, fantastic legacy policies to carry over - powerful and flavourful. Maya also has no bad uniques; the scout replacement is insanely good, the extra mobility on their ranged unit is fantastic, as is their unique district. Less enthused about Hawai'is uniques, but their primary strength comes from turning water into culture.
Greece felt great on medium difficulty - it's exceptionally strong diplomacy civ, with a lot of that power carrying through legacy policies - but they are reliant on the independent powers surviving. If other players start targeting those, it will significantly weaken them. Even then, the unique district and great people are good. They should work in setting up any type of game.
Mexico, Spain, and Persia all felt very good at doing their respective thing - culture, colonising and conquest, respectively - with a decent mix of units, without being overpowered. The legacy policies for the latter two let you continue their exact playstyle if you want. The only real disappointment was Pairidaeza; I made a handful, but it felt very replaceable by any of the city-state uniques you can get in the next two ages.
Normans were actually a ton of fun to play in their own age; free walls when you settle are great, and the unique district gives you two stats that are always useful. But the most fantastic, impactful and flavourful effect by far is the gold on farms, doubled during celebration. I feel they would be really strong, versatile exploration age pick if you could carry that effect forward, similarly to Hawai'is culture. Unfortunately, it's one of those "plus" improvements, instead of a policy, and their actual legacy cards are very unimpactful, so all you're left with in the modern age is a bunch of donjons and obsolete walls. I'm hoping this is changed, eventually, to bring them more in line with Hawai'i.
Prussia I'm really not feeling, honestly. They're powerful domination civ, without a doubt, but none of it feels very tangible. The extra combat power off the bad diplomacy is an obvious, always-on bonus, but by modern age it gets lost in the sea of the other adjustments. Hussars cannot be upgraded into from all the free cavalry you get slotted into your generals if you warred previously, so I'm still mostly using landships and tanks. Ditto for Stukas; I've built a couple, but it takes a lot of setup to have them follow the frontlines; they might be more critical on the highest difficulties. The unique railway is the weirdest one by far, though. I'm 40 turns in and still not sure how I'm supposed to be using it - I saw some on neutral tiles on turn 1, and the rail stations I'm bulding are the same ones I'd build as Mexico. Their civics unlock some fantastic bonuses once you get to them, but if you're researching them, you're not researching the ideologies you need for a domination victory. Using them off the back of Persia and Normans just feels like an overkill. They might be better pick if you played a culture game before and want to pivot into conquest at the end.
As for the leaders;
It's hard to judge Rizal, as it was my first game and the civs I've picked heavily carried it, but he seemed fine, if unspectacular. The extra happiness and length meant I was in celebration basically all the time, but as others pointed out, this will backfire once you have enough happiness to start one every 10 turns, instead of 15.
Isabella synergised really well with Spain for the economic legacy - no surprise there - but her biggest advantage by far is the one-off gold from discovering the natural wonders. That 300 in the early turns can take you from one settlement to three in an instant. She becomes a bit of a blank slate by mid-exploration, once gold income and costs scale up.
Friedrich, Oblique is a bit of a weird one. The extra range on generals is fantastic - makes all the difference in the early wars - and the extra units spawned by science buildings are really nice bonus if that's where your focus is, but I felt the two bonuses were at tension with each other; if I'm already warring, I rarely needed those extra units away from the front, where they spawn. I feel like I need to play him again to see if I can utilise it better in a science-focused game.
