I have no modding experience, and am completely new to the forums, so I have no idea as to the feasibility of this idea, but I haven’t seen it anywhere else. (please be nice, I know i could be rambling here)
I have seen mods which break down GDP into eg. Industry simulations, but this seems to fall into the same traps as vanilla democracy. I find that once the economic component of the game (as the main big problem) is resolved, it fast becomes quite tedious.
One way of possibly reworking GDP so as to avoid effects stacking (giving you late game max GDP)
would be to have each composite factor of macroeconomic output reflected as a situation bubble in the game - intuitively, I think this could work quite well with democracy 4 format. Since democracy has a really nice way of pointing to causes and effects, this should really be quite accessible for players to pick up.
As high school econ students know, national output, the GDP, is determined by the equilibrium of long and short run aggregate supply (AS) and aggregate demand (AD).
The game could easily have to situation bubbles reflecting each, the former (AS) then affected by the total population and capital stock/productivity of the country. The latter, would be affected by 4 bubbles - Consumption (determined by household incomes), investment (foreign already represented, domestic affected by buisness confidence/taxes etc), the level of government spending (spending minus taxes), and a basic reflection of imports and exports - this could be done by splitting international trade into two bubbles for each or a high low representation. Crucially, government policies, such as welfare spending, infrastructure, cutting or raising taxes would impact the individual components of GDP, which should mean far deeper gameplay. Neglect supply side policies by failing to improve productivity but increasing output through high spending? – inflation. Neglect demand-side policies - high unemployment and deflation.
This would still be very basic, but would more accurately reflect booms and busts and should have the effect of creating new problems for the player (eg: a supply-side or demand-side recession would warrant a different response). The effect of events, such as an international supply shock, or financial crash (with effects on demand) would create a puzzle for the player to resolve, and should mitigate the late-game utopia.
This should also nicely accommodate different individual playstyles (cough ideologies), since some players have repeatedly complained about the inherent keynesian bias of the game, from the left and the right. Simulating output in this way should allow an economic left and right playstyle, and we’d see a nice representation of supply and demand sides of the economic spectrum both meet successes and failures in game.