[llamabeast]

The Conceptual Balance mod is the closest thing to a widely accepted mod (at least on these forums); it aims to make general changes to lots of things in order to provide a bit of balance and increase the number of useful options available to players. New content is added in small amounts - the Endgame Diversity Mod is included, which adds more lategame summons, and some of the weaker nations have gained a little content. In general significant efforts have been made to preserve the theme of the original game.

Since I'm the current maintainer of the mod this sounds a little like self-promotion, but quantum_mechani did all the work which led to it being a widely used mod.