I think there are lots of quick and subtle communications that happen in a team while they're working. The quick "hey where did you check in the change for foo?" or "Let's do this task first, then the other tomorrow" or whatever, that happen in a team very quickly that I think happen better in a physical space then an IM chat or an email. Isolating a team from each other in separate spaces prevents that. But I can appreciate the need for single rooms for people to use on occasion when they need to really concentrate.
Central conference rooms are critical, but don't lend themselves well to casual, quick communications.
> "hey where did you check in the change for foo?"
... and you just took me out of the Zone.
I was about to be intensely productive on hard code for 30 minutes, but now I see it's only 15 minutes 'til lunch. Maybe I'll check email instead of building up that concentration level again.
That same shit happens to me in my open office. The difference is that it's easier for me to dick around for 3 hours instead of 15 minutes since nobody can see my screen or even see if I'm here.
I think, it depends largely on how people work together. In some occasions, when people really work on similar problems on the same part of a project, it could really be like you described. But I have seen that in really rare cases and seldom with more than may be 3 or 4 persons. Not ten persons and also not scrum teams. In scrum teams (as I have seen them), the tasks of the persons are so different, that you seldom have that kind of communications. Also when the micro-communications, that you talked about are between two or may be three people -- there it would be better, if the three work together in one office or if they could go out of the office and meet somewhere where they don't disturb others. In such cases, I would opt for offices of 3-4 persons that work in the same areas.
I would really opt for offices of 3-4 persons. Scrum offices, or team of ten offices are to noisy for my opinion and most of the discussions will be non-interesting for the other peoples (for example developers are not interested in the managers talk or the product owner will not be interested in details from developers work .... also documentation people will not be interested in). If others could be interested or should say something about a topic, it is always better to have a spontaneous meeting.
You can also have a central or conference room for communications, or coffee corners connecting the offices.
I think, Joel Spolsky has shown a real good example: http://www.joelonsoftware.com/articles/BionicOffice.html
His office does give both: Everybody can retreat, but also a huge area to communicate, live and exchange in community.