A mod for Civilization IV or Civilization V (or the new game itself) has to include MORE economic concepts. So far, I've seen very little "real" economics in the game. Have you seen the Commerce Screen in Civ IV? It's appallingly tiny compared to the other screens! And there's nothing interactive! Take an example I've heard many complain about: the treasury system is weak and money-rushing buildings and units requires way too much gold in the early as well as late game. Here's another: corporations don't do enough and there aren't enough of them. Ok, well these are easily fixable. I'm not a big fan of XML or Python or whatever, but even being somewhat computer illiterate, I know this is easily doable.