There's an excellent episode of the games design round table podcast (http://thegamedesignroundtable.com/2013/02/14/episode-14/ http://thegamedesignroundtable.c

There's an excellent episode of the games design round table podcast (http://thegamedesignroundtable.com/2013/02/14/episode-14/ http://thegamedesignroundtable.com/2013/02/14/episode-14/) where Jon Shafer (designer of Civ 5) and Soren Johnson (designer of civ 4) discuss this problem - amongst other things.