This is nice. I like this editor, will try it out. The beginnings of a "mode" exist in vim, with plugins like tinykeymap that let you get into "tab manipulation mode" or "window manipulation mode", you can really do that with anything though, but maybe not as extensively as in Ki. It's quite a neat trick, example that lets you c-w +++++ instead of c-w + c-w +:

  nmap <C-W>+ <C-W>+<SID>ws
  nnoremap <script> <SID>ws+ 10<C-W>+<SID>ws
  nmap <SID>ws <nop>