Good ideas. Personally I'm less of a fan of hard DC's. I like it when multiple stages of success and failure (other than nat 1's and 20's) are getting implemented in games. For example rolling a 9 on check to break down a door with a DC of 10 wouldn't be a complete failure, but it would take you multiple swings and maybe even exhaust your character. Or for pickpocketing someone the higher you role the more of that person's inventory can you access. (Ok, slightly off topic because a skill check, but just to give an example how differently you could handle DC rolls)
