When you want to contact people to collaborate you have two options. 1 - Create a space and add people. 2 - Contact a person. It would be a good idea to change option 2 to allow multiple users to be contacted and automatically create a space. The users of the space could then rename whatever the space name that the system created would. This could eliminate the need to have multiple options (1 & 2) in order to collaborate and simplify the user experience.
The reason #2 exists is to allow for the use case of working with just 1 person but not allowing other folks to enter the space without approval and see all the contents of what might be a private interaction. So there is a use case for keeping that space 1:1, having said that I have myself advocated a change here. The workflow should allow a 1:1 space but then allow the person who created that space to make it a multi-person space. Now when you do that you should provide 2 options to the user 1) Take the content and messages 2) Just take messages. I realize as soon as this is turned on, some customers will want this admin configurable i.e allow 1:1 to become a multi-party and others will also want end users to decide. I hear all this is being looked at but right making a 1:1 space into multi-party isn't there for privacy reasons.