Pedestrians with some sort of mp3 player, working payphones, useable airports and city buses, the ability to swim under water, street lights with turn signals, the ability to use turn signals in cars, cops riding bicycles, destructible environments and no I'm not JUT talking about lights and signs and garbage cans, NOT getting shot at for resisting arrest, more animals, working amusement park(s), more weather options like snow, hurricanes (stronger storms), maybe an earthquake within the story since it DOES take place in CA, entrance to just about any building, trains like 'GTA: SA' had, and anything else I missed I'm sure will be mentioned in further comments.