Clarke batted for a big chunk and NZ still needed a super over to win. So yes of course that discredits the score. A ton on an average pitch is worth more clearly.
The fact, and honest NZ fans know this, is McCullum does not perform when it matters most. Being a good flat-track bully does not make you a good batsman. Being a good batsman means you score runs in competitions like this. His record in such situations is poor, in pretty much every format.