Coming back to this to rescind my previous comment.
I never used shared spaces in my Workflowy with other folks, it was just for me. And so that feature wasn't terribly useful. Now that I'm sharing a workspace in Tana, and now that some of that work involves presenting to clients, I will say — we would definitely use this. Especially after seeing it demo'ed and teased in the recent AMA... So I'm giving this a little "nudge" here on Ideas: despite previously voting for it in solidarity, I'm now also voting for it selfishly.
Coming back to this to rescind my previous comment.
I never used shared spaces in my Workflowy with other folks, it was just for me. And so that feature wasn't terribly useful. Now that I'm sharing a workspace in Tana, and now that some of that work involves presenting to clients, I will say — we would definitely use this. Especially after seeing it demo'ed and teased in the recent AMA...
So I'm giving this a little "nudge" here on Ideas: despite previously voting for it in solidarity, I'm now also voting for it selfishly. 
cc @Olav Sindre Kriken - main per last night — Look! It actually does already exist!