17. I was using "Ingame Editor Mod" to give city states workers and they were using them just fine. May be that was the an early game, and city states didn't have technologies to improve their tiles. Or, try to give city states wokers from start.
20. More belives, that provide buildings, similar to "pagoda". Just try to start a game, use "Ingame Editor Mod" and give yourself 600-800 faith to start a religion. And in followers belives you will find "Pagoda", "Mosque" and "Cathidral". These are buildings, you can not build normal way, but you can purchase them with faith. And these are the most wanted religious bonuses. Just add more similar belives, like, for example, "Synagogues" and give them bonus, similar to Pagoda. Or, if Pagoda gives a bonus of 2 happiness|2 culture|2 faith - replace in new building culture bonus to science and make it 2 happiness|2 science|2 faith, and in another building replace culture with production, and so on, may be even a buiding with 2 happiness|2 stability|2 faith bonus. This will make late religions more attractive. I just don't know, how AI chooses those belives, sometimes it seems like it's random. And, if it's not, would it be possible to learn AI to choose new belives?