I'd agree on banks. I'm going to create my own thread just on banks and the use of central banks. In the UK theres a company called Virgin and they span from been an aircraft carrier (all be it with emirates as a backer) to banking ( recently acquired).
Richard Branson epitomises all that capitalisms about, as he started in the music industry with one song ( tubular bells ), then retail and now owns banks, airlines, retail stores ect.

I do appreciate it's more coding but I do think it's required. Maybe a future expansion amongst others that could be added like airport and shipping ports ownership, as thats a huge billion pound industry in the UK, as it is around the world.

It sounds like a good idea, but in my opinion a bit too complex and a bit hard to implement.
Also it would be hard to program an AI response to bank demands

Well, I think that what lacks most are banks.
I mean, private banks. With all the role they play in, well, capitalism.

I know it's getting too far in the game development to add them, and that it's too complex to add it just like you add new products, but it would be really interesting to have add, or to play them.

Central bank could play on the liquidity ratio, they would make money from deposits by putting them on the markets and would lend money to firms

I think THAT could be a real improvement to the game, and a big change. I don't know what the other beta testers thinks of that, but that would be huge, in my opinion.