Basically we're looking at Artists, Merchants, and Scientists working well as specialist slots, Priests possibly being too weak (depending where that free specialist ends up), Engineers and Spies being too strong.
Let's unpack some of this analysis. Artists work well as specialist slots because they allow you to pop borders quickly. This gives you a lot more flexibility when choosing city locations since you can access second ring resources almost immediately. It also lets you settle aggressively against AI opponents without fear of becoming overwhelmed by foreign culture. Engineers and Spies are too strong as specialist slots because they give rise to very powerful Great People. Spy yields also cannot be matched except by other Spies. Basically, these specialists are not intended for the early game. Merchants and Scientists are decent as specialist slots. Their yields are not impressive (0 food, 0 production, 3 commerce is inferior to almost any improved tile) but early Great Merchants or Scientists are an interesting alternative to Great Prophets. Priests are poor specialist slots because they have the lowest yield and are available at Ceremonial Burial anyway.
You'd need to grow your other cities a bit before filling that specialist slot is feasible. Cemeteries are pretty powerful buildings for the era, and make Ceremonial Burial the most powerful starting tech. I don't think it hurts to have either of these weakened so long as we adjust the affected traits accordingly, Spiritual in particular.
Now, here's the thing. Specialists are generally not worth hiring unless you intend to retain them until they produce a Great Person. On their own, their yields are terrible. (Even a mighty Engineer is equivalent to an unimproved plain hill.) That's what makes a free specialist from Cemeteries so powerful: they produce GPP for free. I agree that they are probably too strong for the Ancient Era. But moving the free specialist to the Palace will just mean that 90% of your Great People will be born in your capital, when you consider that it's also your most likely candidate for Wonder construction. So here's my suggestion for the Cemetery:
Cemetery: +1


If you want an early religion, you'll have to hire a priest specialist yourself. Otherwise the Cemetery will slowly accumulate GPP, which you can redeem for a different Great Person once you unlock the required specialist. A free specialist can be saved for a later building.
I'd still like Industrious to associate with engineers and Political to associate with spies, specialist or great, in some way though.
Espionage is surprisingly and frustratingly unmoddable compared to other systems in BTS. Pretty much nothing we can do that doesn't involve EP. I really want Political to have an espionage focus though. Not essential for Diplomatic where it's only meant to be a relatively minor bonus. Need to think of interesting espionage bonuses that won't kick in too early.
Because Great People have other uses that are usually more valuable or strategic, I'm not sure it would see much use if attached to another trait, unless it was strengthened considerably.
Together with the change to the Cemetery, I'd also replace specialist slots with targeted specialist bonuses. And instead of increasing the primary yield of specialists, I'd diversify, as follows:
Creative +1


Enterprising +1


Industrious +1


Political +1


Progressive +2


Spiritual +1


That will encourage those particular leaders to hire those particular specialists and settle the corresponding Great People. It won't overload any one specialist, as bonus science on Scientists or bonus espionage on Spies might. (Even adding food to the priest will keep it in line with an unimproved riverside plains tile.) Ultimately, without free specialists from Cemeteries, bonus specialist slots aren't terribly interesting. Most specialists are available fairly soon, with Libraries and Theatres and Markets. And later you can have a limitless supply with the right civics. I'd save the specialist slots for UBs, which I definitely want to have a look at soon.
I'm still very tempted to leave Progressive with a free Great Scientist per era. It adds variety, makes thematic sense, and I don't think it's overpowered compared to a scientist slot. Build research at 100% is an alternative but I've already used the wealth and culture equivalents and would prefer to avoid it for variety's sake.
The problem with this is it opens a second stream of Great People, alongside GPP. I'd probably use those Great Scientists as follows:
Classical Era: settle in capital
Medieval Era: Golden Age
Renaissance Era: build University (probably also in capital)
Industrial Era: found Corporation
Modern Era: Golden Age (with other Great People)
Now, that doesn't sound too bad, except that I'd simultaneously use GPP to produce all the other Great People I might want, for religion, trade missions, infiltrations, and so forth. No other leader would have that option. And ultimately, I'd be discouraged from hiring Scientists, since I'll be getting Great Scientists for free anyway.
Something that is worth considering here perhaps is that many of the new and redesigned UUs have free promotions. I specifically avoided giving Combat I, Medic I, Commando and Sentry to UUs so that they wouldn't clash with traits.
Right, I haven't had the chance to look at all the new UUs yet, but I still think you can add free Flanking I and Drill I promotions to leader traits without issue. They're also entry-level promotions, and I expect most UUs have stronger bonuses than that. (If not, we can always tweak them.)
Anyway, work on a 2nd draft is underway, lots of new ideas and considerations to juggle. Keep your suggestions and criticism coming.
I'll hold off on a second draft of my own until I see yours. But I have been trying to come up with ideas for non-standard bonuses. Are any of these possible?
- Free Buildings Upon City Founding, i.e. free Aqueduct in every city
- Free Culture Upon City Founding, i.e. cities start with 15 culture
- Bonus Culture Upon City Capture, i.e. 25% total city culture added on capture - If a city has 100 culture when captured, the conqueror receives 25 free culture, such that the city is 20% native (25/125) and 80% foreign (100/125)
- Automatic State Religion Spread Upon City Capture
- May Choose Great Person Type, i.e. When a GPP threshold is met, an event popup allows the player to choose which type of Great Person is born, from among the types possible
- Permanent Peace with the Barbarians
- Bonus Commerce Per Culture Threshold, i.e. 0 gold for Poor Culture, +1 gold for Fledgling Culture, +2 gold for Developing Culture, etc.
- Bonus Units at Game Start, i.e. bonus spy
- Other Players May Not Issue Demands
- Double Movement on Roads
Also, we used to have "improvement costs refunded" as a trait bonus. Was there any particular reason it was cut?