Can you find me one quote of this term outside of Oblivion? Radiant AI is a proprietary software of Bethesda. It is nice to know it became a general term though, perceived in minds of gamers.
look for a moment, put the Radiant AI term out of your mind.
now
NPC's have a schedule, and they "look" like they are doing stuff so everything isnt static like an MMO ala Morrowind without mods
Gothic 3, old game, did this ages ago nothing new same for Fable 1, released HOW long ago?, nothing unique to Oblivion, and Todd in the usual bout of down playing Oblivion like all devs said.
the NPC's didn't do much of anything.
Skyrim me thinks changes that.