First of all, I very much like your reworked treatment of progress. Some very good thinking here.
I also generally like the fact that being at war slows down (especially) your culture progress speed but boost your army and navy progress.
I would like to suggest a few additional features, though:
I would like to see an allowance made for acquiring an advance from another, more advanced realm. And ideally, this should not be allowed as a diplomatic action, as in “buying” a technology, but rather as an event. When civilisations have good relations, there also is some cultural exchange, and the less advanced civilisation starts to adopt the ideas of the more advanced civilisation. That’s a natural process, and I think it should be reflected by events with a “mean time to happen” influenced by several factors:
Geographical Proximity: Civilisations that have a common land border or border on the same ocean region have a higher rate of traffic between them and thus a stronger exchange of ideas.
Cultural Proximity: Civilisations with the same culture and/or religion are more on a common ground than those of different ones, and have conversely an easier time exchanging ideas.
Relations: Civilisations with good relations have closer dealings and thus a stronger exchange of ideas. I’d suggest minimum relations of +100 for the event to fire at all, with increased chances for better relations and tributary relationship.
Open-mindedness: Civilisations that have more liberal, open-minded ideologies (i.e. national ideas) are likelier to adopt foreign, new-fangled ideas. The settings of the sliders for Protectionism, Censorship, Militarism and Piety should all have an effect on the likelihood of the event. If censorship, militarism and piety seem strange choices I’d like to say that the first one reflects how uninhibited new ideas can spread, and that the latter two have a connection to how conservative a people is and thus how ready or reluctant to adopt new ideas.
Then, and on an entirely different note, I would really like to see some possibility for the player of putting
minor emphasis on one area of research at the expense of others – if not overall, then at least in the army/navy branch of research. I would like to be able to either develop sea power at the expense of land power, or land power at the expense of sea power, or to develop both equally.