This forum not being very accessible to French (non-English-speaking ********), I would like to contribute in the name of my fellas...
First thing, apart from the basic rating, I think there should be some consideration given to the capacity to win a game on major competitions.
As proposed by some others on the topic, Flair should have way more importance. Take the example of the French National Team: they are far less consistent and certainly also less physical and technical than the All Blacks or RSA, but they are able to win a major game with guts and a touch of talent and flair. I'd say the same of Wales, who on the paper does not have the best team ever, but they are specialists of winning a game by scoring to tries after the 75th minute.
Some kind of capacity for some teams to react under pressure would balance the whole rating. Because once again, if you look at the current results, the South Hemisphere teams are better prepared, and look to us frenchies like killing machines, but there is not a single world cup when we didn't show up with some surprising results, while we are regularly ass-kicked during the test-matches...
So the point is that if you make RSA, AB and Australia's ratings look realistic and that it is the only thing taken into account in the game, Northern Hemisphere teams will not even compete (apart from England, who has a cold and methodical style) while, Iam sure than once again, in the REAL 2011 RWC, France, Wales, Ireland, Scotland and some others will not be ridiculous.