No, I wouldn't want to give that impression.
The U.S. is still by far the biggest supporter of NORAD in terms of resources, financial and otherwise. It's simply a unique relationship now that USNORTHCOM and NORAD are housed in the same building—indeed, the commander of NORAD is also the commander of USNORTHCOM—and we in Canada are getting more insight into the concerns of U.S. vis-à-vis the homeland.
NORAD, of course, is still charged with looking for traditional foreign defence threats, but now 9/11 has shown us that you can't only look for the missile coming from outside of Canada. You also now have to be far more aware of what's happening. Really, that was the impetus behind the addition of maritime warning to the NORAD missions.