The biggest thing McCullum has done for NZ is catapult the sport of cricket into the same sphere as rugby union.
Everybody in that country wants to be a rugby player, but McCullum has increased the popularity of cricket - and that deserves recognition.
Williamson should look to emulate his set-up. Of course, he'll want to stamp his own mark on the team, but if it ain't broke don't fix it.
NZ play the game the right way.