But decorators are just syntactic sugar around functions. You can have them now with;

    var deprecated = function(fn) {
       console.warn("Deprecated!");
       fn.apply(this, arguments);
    };

then

    var oldMethod = deprecated(function() {
    });

In ES7 you'll be able to call decorators with the new syntax:

    @deprecated
    function oldMethod {
    }

But nothing stopping you writing modular code now. The complaint about 'I have to write console.warn everywhere' seems to have an obvious answer; 'no you don't'.

As for other issues with ES6+7, the new syntax trades a few characters for a lack of clarity about what is actually happening.