The short version is that open offices promote less face-to-face interaction, more IM/Slack and more email.
So we have more digital distraction and less of the thing that the office was supposed to promote.
This quote sums up my feelings on the open office well.
When you remove any semblance of structure to human interaction, people get overloaded and withdrawal into private, electronic cocoons.
I hate open offices. Why I don’t do hot desks at coworking spaces, though they wouldn’t have the IM component because you don’t work with everyone in the office.
I’ve gone so far as to turn down an open office job because I told them they weren’t getting the productivity they wanted out of anyone, and I wasn’t going to have that type of work under my belt.