Imho, financial trait is far too powerful. Especially when combined with 15% cheaper purchase policy, republic revolution and later with big ben and maybe also 20% cheaper military units purchase .. then, buying stuff is really cheap and for one gold you get far more than one hammer.
And other traits seems to be quite worse compared. Especially the +1 culture - well, maybe it's good for the first some turns but quite soon, the effect is hardly noticeable and there are some policies which also increase city cultury by 1.
Or the industrial trait, well 20% wonder production in the capital - with workshop it's only 12,5% real increase and the advantage lowers by the time through other buildings, which increase production by %, and if building wonders in other cities.
May the one or other trait should become less powerful, but financial is too strong. May change financial trait to +20-30% gold in capital/every city - so it would also lose power by the time through modifications through other buildings.
Another idea would be to add +1 hammer for each engineer slot a building provides for industrious, +1 gold for each merchant slot a building provides for financial and +1 culture for each artist slot a building provides for creative trait.
Spiritual may needs an early boost, like +50% through happiness buildings / all happiness sources
Phil could also need some boost, like a production boost for buildings with specialist slot.
.. however nerf financial
another problem is, that hospitals needs a aqueduct , so only cities at rivers can build hospitals and later the +growth building. And with the +growth building, which you could build if you have local wine ( actually don't know the name ... ) you get quite much food saved after citiy growth and this city becomes a monster
And it's nice to have wonders with +50 xp for melee/mounted units, but especially the +melee xp wonder comes little bit late. Without a GE to boost the wonder, I don't see any chance to build a melee with this starting advantage. The +50xp for mounted units can be used to build super cavalry units, which later become super tanks. And it's possible to be not allowed to build lancer nor cavalry.
And some bonus ressources are too strong, cows with taverns ( at begin ) and stone all the time. Stone unlocks many buildings and creates sowith monster production cities. ( foundry, steamworks, tile production, ... )
Fishes and other sea ressources boost a city maybe also a little bit too strong, even at the begin .. may give docks only +1 hammer, but also lighthouse +1 and maybe seaports another one extra. A well placed early coastal city becomes an early monster city imho a little bit too much.
Maybe have also a look at pagoda preq.
Another trouble building are imho train stations, especially at larger maps. Larger maps allows more cities and sowith more trade and when building/buying a train station for additional 100 trade income, then it isn't a hard decision for what I use the short coal. Also because of the +10 culture per policy.
At policies I find myself always picking tradition first ( + hammer + food/science ) and later by picking policies from all trees, but only go later deeper in the trees. Imho, at begin the +hammers in the capital seems a little bit too strong, besides the 15% purchase ( which is even better than their final ) and I don't think, that it should be allowed to get policies from every tree, everytime without any disadvantage. Likely - unlock 5 policies to be able to pick another tree, unlock 15 policies or one of the deepest one to be able to pick a 3rd tree, unlock 25 policies to be allowed from any tree.
And it's nice, that only one of the deepest policy can be annected and can't switch, but if you get +1 food per specialist first and later halve food per specialist, then the +1 food policy is reseted and you can enact the +2. And the biggest problem I have is, that it isn't mentioned at the +1 food policy, that you can't have the havle food too - indeed, it would lead to some funny results

- but it is mentioned at the halve food policy.
Guild hall can't be bought.
Maybe have a look at revolution too. I find myself always picking despotism and later republic/democrazy. And there especially the +1 free policy seems a little bit too strong. But maybe I'm wrong there. However after the first few revolutions I can't understand the given numbers at the revolution points race.
Overall I think, that with the time too much research is generated, because too much population isn't punished and research is more or less tied to population. May decrease rp per pops, when cities hit a certain size, or the civ research is the root of the sum from all city's research to square.. (Xn0^2 + Xn1^2 + ...)^(1/2) --> would benefit small empires with one huge city and punish large empires with rather small cities.. or increase research cost beginning in the medieval slightly up to double at modern techs.
But an increase in cost would punish the late ai further. If I shouldn't be the supreme #1 at the begin of the industrial age, I will be it at the end. At begin I'm not able to expand that fast with even that big army, but they are not able to handle when the game advances. It would be nice, if the ai would be weaker at begin and stronger at the end ... if someone hits a new age , every ai get +1 difficulty lvl
I played now 4 games and it feels more civ than civ 0.5, especially with less/none city states. Don't know if there is any mod, which balance cs a little bit, but default I would disable them ..
great mod !