I know this probably goes to the heart of how the game is programed - but would it be possible to have shifting demographics as the game progresses?
For example (and what would probably be the most relevant example)
I run a nation with 25% in the Poor group. I create policies to help the Poor, this rises their option of me, equality, and their standard of living - but they always remain poor, fixed at 25%, none shift into middle class (which may give me a temporary popularity boost in that demo which could slide back down, as they become more concerned with middle class issues).
I’m not saying it should be possible to reduce poverty down to 0%, and I know this would be very difficult to implement, but polices designed to help reduce poverty should ultimately do that. Reducing the number of poor would reduce the cost of these policies, and that is the ultimate pay off for investing in such policies. Also, middle class benefit policies such as income tax cuts and mortgage breaks could raise citizens in the wealthy bracket. In this way you could lift the wealth of your nation.
A way around this (and this way already happen in the game) is to lessen the cost of welfare policies as the poor become better off and reduce the negative effects of policies (such as sales tax, tobacco tax, etc) on the poor as their standard of live improves and becomes more secure. This wouldn’t change the social dynamics of the game (previously poor people swelling into the middle classes and becoming more concerned with middle class issues) but it would reflect the pay off in the supportive policies. A reduction or cut of supportive policies would remove this security, drop the living standard of the poor and increase the costs and effects of policies on the poor once again.
Also, policies that raise the middle class life style would result in equal (or more) mount of funds for the government at lower income tax rates - as more people earn more money.
Sounds like a libertarian dream
BTW - AWESOME game! The increased level of complexity, and most especially the limit on term length provides some real challenges and is a worthy development on the original.