I’m not sure if this has been addressed or not (no results showed up when I searched for it), but now that the game has been made somewhat more challenging with the recent changes, it might be worth adding some additional and pertinent revenue sources for players to choose from.
One that I desperately wanted in Democracy 3 and that I hoped would make its way into Democracy 4 is a financial transaction tax. Originally envisioned by Keynes, it has more recently made appearances in the aftermath of the Great Recession as a way of dealing with speculation in financial markets while simultaneously raising revenue for governments. Some countries already have a version of such a tax, while the European Union has been looking to introduce it for some time now.
It could bring in a moderate to high amount of revenue, depending on where the slider is, with the following effects:
-Slight to moderate decrease in GDP
-Slight decrease in business confidence
-Detrimental effect on capitalist, wealthy opinions
-Increases tax evasion at higher levels
Along with any other effects that you might find appropriate.