The differences between NH and SH rugby go a whole lot deeper than stats.
In the last few years, the perception has been that the NH plays a much more conservative, forward oriented game; moving from set piece to set piece, kicking for territory, slow ball at ruck time, lots of mauling and strong defensive lines. Players concentrate mostly on their core roles and very little outside. Meanwhile, SH holds a back oriented philosophy for the most part, playing expansive rugby, running the ball as much as possible and encouraging players in all positions to develop a wide range of attacking, defensive and ball skills. South Africa and Argentina have not been quite as adventurous when it comes to open running rugby as Australia and New Zealand, and their style has really been something of a compromise between the NH and SH styles.
However the NH forward oriented v SH back oriented hasn't always been the case. In the past, the All Blacks were known more for their uncompromising tough forward play, and playing 10 man rugby. Then the 1971 Lions toured New Zealand; they won all of the Provincial tour matches (19 of them) plus matches against NZ Universities and NZ Maori, and the beat the All Blacks for the first time in a series 2-1 (1 drawn). They did so using great back play and strong forward play. However, that changed over time, and IMO, the beginnings of that change coincide with the change to professionalism.
The way the game became professional in the NH and SH was totally different, but they both had one thing in common... they were trying to fight off the World Rugby Corporation (WRC) run by media mogul Kerry Packer, who had been responsible for the 50 over One Day Cricket and coloured clothing (known at the time as the Pyjama Game). I'm not going to go into the details here, but as I have done before, I recommend you get hold of a copy of a book called "The Rugby War" by former Wallaby Peter Fitzisimons.
[TEXTAREA]Bestselling author and Sydney Morning Herald journalist Peter FitzSimons takes us to the very heart of the battle which evolved from the continuing friction between the business empires of Rupert Murdoch and Kerry Packer. From the first wisps of smoke that appeared in a boardroom in Sydney, a War suddenly ignited around the world. Some of the game's greatest players, including the captains of Australia, New Zealand and South Africa, came to place their trust in a small group of men with an alternative vision to the establishment's - men who were backed by Kerry Packer. Peter FitzSimons details the consequences of this change, one of which would see the sport abandoning a commitment to amateurism which had survived more that 100 years. Bruising, bloodied and bitter, no one knew just how close the Rugby War came to having an entirely different result.[/TEXTAREA]
The upshot was that in the NH, the RFU and FFR, and to a lesser extent, the other Home Unions; organizations run by stuffy old gin-swilling blazers with Victorian mindsets, fought tooth and nail to try stop professionalism from infecting The Great Game. While they sat on their hands with their heads buried in the sand, in total denial and hoping it would all go away, the Clubs stepped in and the rest is history. The National Unions lost control of their players as they were all systematically contracted to privately owned clubs.
Meanwhile, in the SH, the National Unions knew that professionalism was coming, and that they were not going to be able to stop the tide, so the unions set about signing the players to ensure that Packer's WRC circus didn't get off the ground. To this end, the NZRU sent the councillor Jock Hobbs to front as a central, unifying figure to resolve the rift between the players and the Union. Many of New Zealand's top players were set to defect to the WRC, and it was considered in many quarters to be a done deal until Hobbs worked for over six weeks to secure the players' signatures for the NZRU. This earned him the label ; "the man who saved rugby".
IMO, the whole philosophy of rugby, and the way the game is run in the two hemispheres is part of the reason why they play the game so differently. In the NH, its Club oriented; for Clubs, survival is important, relegation is a financial disaster. Attitudes between Clubs and their National Unions are strained at the best of times, often antagonistic, and sometimes verge on hostile
In the SH, the elite competitions are are ring-fenced (no relegation) and are run by the National Unions who also own all the players contracts. The level of co-operation between franchise teams and the National Unions are much higher than in the NH, as they all work towards having the best National teams they can.