TBH I've found myself using juggler's tabs like a kanban board.
It'll certainly let multiple people share the same live session, so that tab list would act pretty much like a live shared kanban board. If you're all happy working on the same folder at the same time, then that would work! I guess that just by adding something like per-tab worktrees it could actually be a pretty good team server.. hmm.. Hadn't really looked at it like that yet, but that' interesting
The first orchestrator I built was a kanban board that spawned a vscode session per task with a plan file in it. Nice contained way to do a chat session, you can review the files and make edits, and close it once it's done. Very slow and heavy though. So that way of working resonates with me.
For some more unsolicited feedback: if that's how you use it why not pitch it that way/ make that way of working more obvious? Bug tracking and todo's jump to mind for me. For example: I want to write a prompt to fix this bug at some point but I need to think more about it. Right now I just need a place to jot it down for now so I don't forget.
Re: collab - managing edits and other state (builds/lints/test processes) is definitely a tricky problem. "Frictionless" worktrees is an interesting idea. That often seems like the "right" solution for how I'm working but it's too annoying to do for smaller changes. Doing that well would be a reason for me to give this a try.