Emacs is essentially perfect. The core of sketchy C is a bit of a liability but mostly works fine. The layers of lisp on top have been evolving for decades.

I don't know what standardisation you're referring to, but feel free to change the key bindings to whatever standard you prefer.

Built-in? There will be multicursor things on melpa, install whatever sounds plausible. The distinction between ships with emacs and added post-install is minimal.