We have many projects moving through our office simultaneously. Many people are involved in many projects, and their involvement might vary from being designer or drafter, to just being a reviewer.
A regular point of pain is where each project needs to authorise access to each person to a session. It would be useful if a company could choose that the default (for them) is that sessions are open to any users within a list of users. That way, sessions would be more similar to PDF files on a file server.
This friction was enough for us to give up on sessions, but it does have advantages, and if this was fixed, we would move back.