Whenever I see a new feature proposal for a programming language, I like to check how a language in the lisp family could solve the same problem with a macro (not trying to point out who is better than who, it's just for fun). For example, this 3-liner would get you the "multiple array unpacking" in clojure:

    (defmacro pep448 [f & args]
      (let [unpack? #(and (list? %) (= (first %) '$))]
        `(apply ~f (concat ~@(map #(if (unpack? %) (second %) [%]) args)))))

which can be used like this:

    (pep448 + ($ [2 3]) 4 ($ [5 6 7]))
    => 27

A bit verbose, so you probably wouldn't do it this way in real life. Thankfully there are generally easier and more elegant ways to handle this kind of situation.