We need a feature that will allow us to have synchronized playback from the same account across multiple devices simultaneously. This would allow for seamless transitions between rooms or floors that have speakers hooked up to different devices. It would especially be nice at parties so that there is musical continuity between all the rooms. It would also be good for when you leave your house you can just slap your headphones on and continue from where it was playing in your house.
Example: I have a computer in my room and speakers in my kitchen. When I do chores, I often go back and forth between the rooms and It would be rocking if both rooms were playing the same music at the same time.