I don't know, this seems reasonable. I already know how to select, copy, and manipulate text in my $EDITOR. Why would a terminal multiplexer try to implement all of that rather than just let me open the terminal in my $EDITOR?

I'm not opposed to using the same shortcuts as editors (which is what tmux already does; you can even pick between emacs and vim shortcuts, in addition to configuring your own); there's just a lot of other stuff I _don't_ want from a text editor for my existing terminal output, like, editing text.