I don't think it is necessary to tie the PureMVC JavaScript port to any third party library like Obj or MooTools. The prototype linking for simulating OO is not too difficult, and once implemented can allow the JavaScript port to be used with any 3rd party JS library that implements an OO simulation scheme for creating subclasses of the PureMVC classes.
Many websites that can benefit from the JS PureMVC port already have committed to one library or another. This means that the decision to use PureMVC or not will often come down to the question of whether or not the site has to include yet another 3rd party library on the site in addition to PureMVC and what they already use.
I've attached a version of the port that has no external dependencies. I have not tested it much, but you can see that removing the dependency is not complicated. It will also not prevent using the PureMVC "classes" with 3rd party libraries for creating subclasses.
If I didn't make any mistakes in the attached file, you should be able to drop it into any web app already using either the Obj or MooTools JS PureMVC (replacing the current PureMVC file), and it should work with no other modifications. The difference being that the same file can now also be used in other web apps without the Obj or MooTools dependency.
Thanks,
Matt Miller