From what I've seen with projects like this, the successful ones do a good job of 'sticking to the mission' of faithfully recreating the original game in a modern engine (openMW, daggerfall unity, all my points of reference are TES related)

The neat part is that they are open source, so anyone who wants to take it in a different direction can fork it. The multiplayer version openMW being a great example of this.

you may be interested in https://www.paxhistoria.co/

not sure if serious...

You are getting downvoted, but this is a cool idea. Diplomacy has historically been a weak part of the series, and being able to shore that up may be a lot of fun to play against.