Darn you, Maldur. You used my best example.
http://www.mayfairgames.com/mfg-shop/rpgs/underground/qps/ug350.html
Underground has a BRILLIANT mechanic for changing society / the environment / the world that scales fabulously (change my community group... change my community... change my city block... change my whole town... change my city... change my State... change my country... change the world!) and that handles any kind of changes you really want to enstate.
In my opinion, EVERY RPG game can use these rules, ironed out a bit to work with variant systems / settings.
Tinner - while I wasn't fond of the Universal Table in Marvel, the version they implemented for Gamma World 3e was obviously the result of several years of playing games with that table until all the kinks were ironed out. Not necessarily the best system, but a fantastic implementation thereof. (Just read a little further, yes, the same one that WmRAllen talked about).
The lifepath rules in CyberPunk 2020 (updated from 2013, and based on rules from somwhere else, I've been told, but can't remember the 'real' origin) - great chargen system.
The introduction of the ability to modify the game through character-earned points, first introduced in GhostBusters, I believe. Effecively a nice Fate Point / Hero Point system used to save your own butt.
Automatic Success rules in the StoryTeller system. Can someone point me towards the origins of these? I know there were automatic success rules in DC heroes also...