The D4 model incorporates a lot of improvements under the hood compared to D3 which I wont bore everyone with (and they are still changimg), but one area we did not change was that we are simulating 0-1 values for simulation and do not model accumulators at all.
Thats not to say its impossible, or even mega-hard, but its an additional level of complexity, with a relatively small use case.
Don’t forget that the sim engine is about 20% of the development cost. There is the GUI rework (D4 scales MUCH better, and uses vector art, and unicode), and then the actual content, and then the balancing of all the variables, and also the non-neural-engine extra mechanics like emergency powers, coalitions, media events etc.
Whats quite likely is that when the game is finished and ships with loads of countries, policies etc, which are all balanced and fun, then there will be an opportunity to see what additional functionality can be added, with modders in mind, to increase the underlying complexity for those who desire it 