Support the ability to programmatically split panes, run commands etc
I use this library https://github.com/syohex/emacs-emamux with emacs, and there is a similar library called vimux -- these are useful for running tests while editing the corresponding files. However they force you to run inside a tmux. Would be nice for iTerm2 to natively support this functionality.
I expect this is possible a la https://github.com/TomAnthony/itermocil via AppleScript, but a simpler API (like tmux!) would be great!