I've seen all these before and it makes me wonder why someone doesn't just make a different version of emacsen like guile-emacs. There must be a lot of inertia behind emacs and substantial amount of development effort to make all these changes that keeps competitors to gnu emacs from progressing to replace it.
Because of GNU Emacs biggest strenght, which is also it's biggest flaw: the mountains of existing code. Any new emacs must support what emacs already offers. And this means not just to be able to run the code, but to also support the huge amount of special and exotic features that Emacs offers. Guile-emacs for example has a pretty long history on fighting emacs-strings and it's special features.
There is the general believe that users don't wanna change from emacs away and any new emacs should be ~100% compatible to old emacs. But history has shown, people will not settle with inferiour clones. So many work will be neccessary, whatever someone will build to replace emacs.
