Comparing the mathematics of the McIntyre system to the new NRL (and AFL) top 8 system:
Team 1 has the same chance to make the GF (about 57% to make the GF in McIntyre and new NRL system, if about 65% likely to win their matches)
Team 2 in the McIntyre system is about 7% more likely to make the GF (about 57% to make the GF in McIntyre vs 53% in the new NRL system)
Team 3 in the McIntyre system is about 17% less likely to make the GF (about 28% to make the GF in McIntyre vs 34% in the new NRL system)
Team 4 in the McIntyre system is about 34% less likely to make the GF (about 20% to make the GF in McIntyre vs 30% in the new NRL system)
Team 5 in the McIntyre system is about 129% more likely to make the GF(about 17% to make the GF in McIntyre vs 8% in the new NRL system)
Team 6 in the McIntyre system is about 18% more likely to make the GF. (about 10% to make the GF in McIntyre vs 8% in the new NRL system)
Teams 7 and 8 have the same (slim) chance to make the GF in either system.(about 5% to make the GF in either system)
This assumes that the higher ranked team wins about 65% of the time. As the higher ranked team becomes more favoured than this, Team 5 has an even better chance in the McIntyre system, at the expense of team 6, compared to the new NRL system (but a worse chance overall, still, if higher ranked teams are more likely to win; obviously all higher ranked teams improve their odds of making the GF
compared to lower ranked teams if we assume they are more likely to win any given match).
In the McIntyre system, 1 v 8 and 2 v 7 are impossible grand finals, and in the new NRL system, 5 v 8 and 6 v 7 are impossible grand finals.
Home team advantage does not really have to be linked to the method for eliminating teams and sending teams to the Preliminary Finals, though it is in both systems. I haven't adjusted these figures for home team advantage (other than to assume the higher ranked team, who usually gets the home team advantage, is more likely to win).
There is really not a lot of difference in terms of the performance of teams 1 and 2 and 7 and 8, but the McIntyre does definitely five 5 and 6 a better chance, at the expense of teams 3 and 4, compared to the new system (though 3 and 4 still have an absolute advantage over 5 and 6 in both systems).
Is team 4 having now a 30% probability rather than 20% of making the GF worth team 5 having an 8% (nearly the same as teams 7 and 8) probability now compared to a previous 17%, of making the GF? I guess when the 2012 finals start, only fans of teams 4 and 5 will really care. Still, if 5th finish on a roll, they can still win the GF with 4 finals wins in a row (only now they absolutely can not afford to lose their first match).