The current version GCP-HARP-1000 is probably what you meant by second edition over the 2003 original and revised 2004 ICE-3000 versions. It is mostly rebalanced costs for professions, races, spells, and talents along with clarifications, flat 50DP/level, mandatory sub skills, creature and spell creation harmonized with the bestiary and college of magic rules as well as a few other bits and bobs.
Not sure what you found flat or what would interest you.
