I think that for Democracy 3 the game can do a big step forward.
Since democracy 2 has not MUCH different from the 1, i suggest the 3 implement something wich could really change the gameplay.
1st) It has been already porposed: More than 2 parties. I suggest it could change according to the countries, from 2 up to 8 parties. New parties could born during the game, for example if there is some part of electorate wich is unhappy with all the other parties, and some parties could die if they fail totally in the elections (for example if a party expected to challenge for the government and instead receive less than 10%).
So, every real democracy has a Parliament. The election result will determinate the shares of members of the parliament for each party.
There will be another value to add: the affinity between different parties. The affinity will grow or fall according to the conduct of the parties during the years. When there is the election if a party can not reach the 50% he will be forced to set alliances and it will work that way: the smallest party will set alliance with the party which has major affinity with him, and going on this way all the parties will proceed and make a choice. At this point we will see coalitions, and the leader of the coalition with more votes will be elected president.
2nd) The next step, and is what i porpose of new is the implementation of the opposition chance. I see it very limitative to lose the game when you are not elected president. The game should continue, and you will play opposition.
The government would be ran by AI, wich will follow the conduct of the AI leading party, so if socialist will make laws for socialist and so on.
since now we have a parliament, you could take part to the political life also by the opposition desk.
Some laws or policies would require parliament approval, so you will be called to vote them.
There are now two scenarios: if the government if formed by a big 51+% party, wich can decide everyting by its own your opposition would be only nominal, you wont change the policies effectiveness, but you will change the public opinion on your party and on government party, so its always usefull to make opposition.
If the government is formed by a coalition it could happen that the two or more leading parties are not of the same opinion on some critical policies or laws, so it could also happen that with your opposition the law wont pass, this causing a strong loss of consense to the government.
You could also be IN the government coalition (example you have 20% and another party wich is affine to you had 35%) and be elected minister, this causing you to have the chance of promote new policies (only those which would be allowed by the president), so you could have a chance to improve your popularity between the public opinion.
I think theese changes could really give this game the input to become not only a leader of this gaming sector, wich maybe it already is, but also a leader of the strategy and managerial game sector, wich really need a deeper version of this wonderfull game!