I've seen somewhere java scripts with snow falling down and waves of water. So in winter time it'll be good idea to add snowfall animation to streetview. And wave animation for water objects. Also sound files with birds singing should be added without "mute" option Also pegman can be animated. He may run along the streets smiling and showing us sime hints for example.
Of course some people may not like that. But that's not problem. Simply streetview will be banned in 6.0 to help promote 7.0