Instead of losing all of the signals from in person communication, the accidental bump into's or a glance causing you to notice someone doing something relevant to you (or vice versa), you can just walk over to someone else's space and collaborate with them. If they need a period of focus, they can disconnect from the group space and have a doorbell, but it would also be easy to rejoin.
And unlike skype you're not always 'on the call', everyone just happens to be in the same room and if nobody says anything all day it's ok. More to the point you could even mute people if it's not relevant.
I once did an 'always on' google hangout with another guy when I was working on a software project with him. It was remarkably effective substitute for being in the same room. Key was it was always on and we could speak to each other when necessary. Nobody does this although in the companies I have worked in.
Also many meeting spaces have microphone quality issues, and it can be hard to hear people in the other meeting room as they have conversations with each other.
Culturally I think it will be hard to pull off, virtue of video conferencing not being used in the same way today.
I'm always surprised by the fact that more companies don't adopt the "always on" google hangout. It's literally in the name of the service, "hangout" yet people use it like a traditional conferencing tool.
If more people adopted it as a ROOM that you all worked in, I have a feeling many of the remote nay sayers would at least feel a little bit better about things.
Perhaps some very very clever voice reordering software could help, not sure. For now text chat works better.