I have been doing something similar for years on longturn.org and my advice for the new admins is simple. Don't burn the candle at both ends. Don't take it too seriously. Remember to have fun.
It's easy to become too ambitious and try to make all the improvements to happen at once.
We had some player(s) who were using offensive city names. Not the f-word or something similar. The city names reminded us about the darkest hours of the human race. For sure some were offended, but in the end if you want to play as such a nation, it was allowed. We just asked if this player really knew what he/she was doing. And yeah, sure those nations were attacked and wiped out really fast.
Very few people remember what happened with Greatturn. Even less people know what really happened. My guess is that too much was going on and the community wasn't just up to the task.
When we add new stuff to rulesets, most of the time it has been a good idea to make new features slightly too weak or too expensive. Too strong or cheap risks breaking the game but too weak or too expensive just make the new features less useful.
Planning and discussing Freeciv Longturn gaming