They should make the software adapt to different times of the year by using the in game date/time. Especially around holidays. Xmas would have snow, lights, Xmas theme around the city. Maybe the city is under snow and there could be a mode to help clear it out.

Even in attract mode it would have a certain holidays showcased. (Xmas, Halloween, Thanksgiving, 4th of July, Easter, ST Patty day, etc.)

And it would be really cool when the game is in attract mode the camera would ID you or your family/friends when walking by and say something nice or play a favorite song, etc.