I would really like to see this kind of work be done upstream. Emacs still looks the same as it did decades ago despite other editors advancing and becoming more user friendly.
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In comparison most other languages are 'closed' - e.g., C is a closed language. Its spec is finite and fixed (C99, C11, C17, etc.). You can genuinely master it: all keywords, all standard library functions, all undefined behaviors, all edge cases. There's a ceiling.
Lisp is unusual, The language itself is a tool for language-building. Lisp is 'open'. There's no canonical "complete" set of what exists. Thus there's never completion or "mastery"