I’ve given this a lot of thought over the years and the biggest conclusion I have is that there’s no real “killer feature” in any of this that makes it spectacular, and maintaining backwards compatibility would be critical to let anybody use it. Still, I like the idea of splitting each command into a separate PTY, I wonder how good a TUI replacement for tmux built around this could be (yes, gotta start with the TUI before you think about a completely new GUI, again for the interop).