Unfortunately most open office have no such space. Not even the toilets (multiple cramped stalls? hell no!).
Everywhere you go and at all times there are going to be people. I think that is the problem.
I think office design should favor more of a compromise between the two groups.
For me a small office with 2 or 3 people is more stressful, it makes me more aware about what's going on around me because it's a more personal space. If you don't connect with somebody in there, the bad atmosphere is going to fill the small office very fast. My bubble is going to trip onto somebody else's bubble more often than in a big space full of people because there's less neutral space around.
Not sure if that makes sense at all... but it does to me.
Extroverts become uncomfortable with a lack of external stimuli and thus prefer to surround themselves with stimuli.
Introverts become uncomfortable with too much external stimulus and thus prefer to isolate themselves from excessive stimulus.
To me that basically directly quantifies why some people thrive in an open office and other suffer. I'm not sure what the solution is to requiring essentially two different environments depending on a person's makeup.