I'm against this clause. It gives the executive branch of the government (the PM and Cabinet, basically) far too much power over the judiciary. The Supreme Court exists to make sure the ruling party does not make any laws which are unconstitutional or violate our freedoms. If a PM (or provincial governments) can over-ride any such ruling, then what is the point?
I personally don't have a problem with Quebec's language laws; I think provinces should have the power to decide what language to use in their government, but that goes for outside Quebec, also, where French serves little use but is forced upon the provinces. The best way to appease the provinces is simple: a Senate with upon equal representation for all provinces, much like in the United States. What is known as a Triple-E Senate (for Equal, Elected and Effective). This won't happen at the moment, however, as the Senate is currently filled with Liberal or Conservative cronies, and the ruling party would be foolish to give up such a political advantage.