where the world revolves aournd itself, meaning you can follow some character and see him walking into a dark alley and dod rug dealings and do new stuff all the time, vs walkign up tos ome other nameless character going aorund their business (going home/waking up tow ork/etc.) and have the game be liek a real world, and have unlimited playability cause you could always explore new character throught the game and make them do random things each time (like random generated dungeons) and some heavy hitters do some things like I said that influences the whole game. Not just the missions but you could play around by yourself with real ai not just some random rpostitutes or people walking through the streets but each fo them ahving a unique ai and eprsonality. kind of like gta meats the sims 2 or something.
-= Double Post =-
like you could go in san andreas and run into a gang shootout and see some dead bodies and you come back later and yous ee 3 of those same guys still alive and 5 new oens in their crew for instance selling drugs. Or like a mmorpg where it is a evolving persistant world, maybe they could add network updates once in awhile and support the game like most pc games which have free patches.