> The real problem is the core NodeJS libraries aren't promise compliant.

This isn't a problem at all in practice.

To say that node core is not "promise compliant" gives people the idea that there is something that prevents them from using promises in node. In reality, most promise libraries have a "denodeify" function that will convert any function that expects a node-style callback into one that returns a promise instead.

  var fs = require('fs');
  var rsvp = require('rsvp');
  
  // Create a version of fs.readFile that returns
  // a promise instead of expecting a callback.
  var readFile = rsvp.denodeify(fs.readFile);
  
  readFile('/etc/passwd', 'utf8').then(function (contents) {
    // do something with the file contents
  }, function (error) {
    // handle the error
  });

It is similarly easy to convert functions that expect other types of callbacks (read: not node-style callbacks where the first argument is always an error) to functions that return promises using deferreds.