I see it as a skill tree in a game like Diablo II. A tech tree is a pretty good comparison as well. Having every skill have positive effects only is pretty dull as well. It's hard to replicate historical situations like Korea's extreme isolationism in Joseon dynasty Korea from 1600-1900 (higher social stability at a significant cost to science and technology leading to stagnation and severe decline), Russia under the Czars/Czarinas (placating nobility at the cost of the peasantry and significantly lowering production), etc. The real world had plenty of tradeoffs where a national policy could be positive in some ways and detrimental in others. It makes a choice truly meaningful. Civilization 5 is consistent though, in trying to remove negative things that might upset casuals, newbies and soccer moms. No random events to spoil your day, no nasty results from goodie huts, wimpified Barbs, only positive skill trees, etc. Hopefully modders will save the day (when the source code gets released) for people who are not satisfied with this arcade style level upping.