A distinct point. Irrigation works on the sheer scale it would take to irrigate such a large territory would be difficult to operate without industrial machinery to tap the aquifers. Though I like the idea of supplying water through wells; it would help deal with situations where for reasons of geography there's a large fertile territory that can't be irrigated because you can't get fresh water over the hills and don't want to chop down forest tiles.
In that case, I say we delay Wells until the Industrial Era! (They would still be called wells, right? We could change the name to Water Pump, but I prefer Wells.) In situations where a region of arable land is surrounded by hills and forests, players would be faced with a choice: chop down some forests; or wait for industrial machinery and perhaps settle another site first.
Inserting the Cruiser and downgrading the Destroyer to its historical role as a support platform for larger fleets would rebalance the tree somewhat, I think.
Sounds like a plan.
Careful, I'm a teacher by profession! Hehe.
Yikes!

I don't mean to trivialize the efforts of teachers but (and you knew there was a 'but' coming) I think there's a better way to model the social value of schools.
The more educated a population the greater the pool of talented researchers to draw upon and new ideas and technologies can be adopted much more efficiently.
This, while undoubtedly true, is perhaps too narrowly drawn. The more educated the population, the greater the pool of talented
individuals: artists, entrepreneurs, soldiers, statesmen, etc. And yet the truly great among them would surely find ways to put their talents to use, formally educated or no...
Schools don't do research directly but they significantly increase the rate of literacy, numeracy, etc, in a population.
Thus, given that schools raise the level of literacy and numeracy in the general population, I would argue their chief virtue is that they bring economic opportunity to the
average person. In modern society, a basic education is the key to a good standard of living. In Civ terms, I feel this best translates to a blanket commerce boost and worker efficiency bonus, while leaving the research to more specialized Colleges.
Schools (even in the modern sense) have been around a very long time, just not so much in Europe [...] I'm deliberately avoiding making the techtree too Eurocentric.
I can't argue with this, except to note that "The Scientific Method" is a rather Eurocentric concept already. (Can you tell that I'm training to be a lawyer by profession?

)
Final decision is that the change will be reverted. Let me know your ideas. One I'm working on atm is making Mines, Quarries, Oil Wells, Offshore Platforms and maybe Workshops cause unhealthiness.
That's a brilliant idea! -0.5 health per Mine (or thereabouts) would be just right. Workshops already suffer -1 food, so I wouldn't add another penalty there. (Though perhaps you could replace that -1 food with -0.5 or -1 health; it might make workshops and the Professionalism civic more popular.)
Well, I'm sorry to say that none my ideas are quite as elegant. But here they are:
1. Per Simon Jester's suggestion, add health and happiness penalties to various buildings and civics. Possibilities include: Markets (-1 health), Jails (-1 happiness), Forges (-1 health with Copper, Iron), Caste System (-1 happiness in 5 largest cities), Fundamentalism (-1 happiness per non-state religion), Authoritarianism (-2 health), etc.
2. Move various resource-related buildings to later eras. The Distillery is a fine example; it is currently available at Chemistry even though distillation was practiced in earlier eras. Likewise, the ancient Weaver could become a classical Tailor or renaissance Mill. Similarly, the health bonus from Cows, Deer, Pigs, and Sheep could be returned to the Supermarket, leaving Smokehouses with the percentage bonus from Salt and +25% food stored transferred forward from Supermarkets.
3. Code the AI such that it will only trade a happiness resource for another happiness resource or
two health resources.
I don't think you need to make many changes beyond that. Though there are now more resources, there will be fewer of each kind of resource on a given map; so even allowing for maximum trading between empires, players will still miss out on some of the rarer resources.
I think the Kiln adds something, a way to get hammers very early in the game.
It is another option of something to build.
I would leave it in, although the increase with techs would make it more interesting.
Thinking more about this, I agree that you could keep the Kiln if you find a way to power it up with later techs. Anything with an interesting mechanism is worth keeping.
I am sorry to suggest that the combination of Camps and Redistribution may be just too good for too long. It might be better to find some other bonus for Redistribution than the +1 coin to camp.
No! I love Redistribution!

But, seriously, I think you may have a point.
Rather than remove the +1 commerce bonus on Camps (especially now that Cottages have been moved to Employment), might I suggest a penalty to balance it out? How does -25% culture sound?
(
How does that fit with Redistribution? Uh, let me think. How about: state redistribution offends elite culture makers.
In the ancient age? Well...)