Number crunching time ....
I have looked at the last 23 rounds of F1 (1991-2013) and simulated what impact awarding double points in the last race would have had on the outcome of the WDC, and whether or not the WDC would have been determined at a later round in the season. Considering that all seasons before 1991 used a points scoring system that consisted of only factoring in the best results (see
F1 points scoring systems), I am only taking seasons from 1991 onwards into account during which all races counted towards the final result of the WDC.
In 23 seaons since 1991, awarding double points in the last race would have extended the season 9 times, and the WDC would have gone to a different driver 3 times. We can therefore assume this new rule will come with a 39% chance of keeping up the suspense for at least 1 additional race, as well as a 13% chance to change the outcome of the WDC.
1991
WDC is determined in round 15 of 16 (no changes)
WDC is Ayrton Senna (no changes)
1992
old scheme: WDC determined in round 11 of 16
new scheme: WDC determined in round 12 of 16
WDC is Nigel Mansell (no changes)
1993
old scheme: WDC determined in round 14 of 16
new scheme: WDC determined in round 15 of 16
WDC is Alain Prost (no changes)
1994
WDC is determined in round 16 of 16 (no changes)
WDC is Michael Schumacher (no changes)
1995
WDC is determined in round 15 of 17 (no changes)
WDC is Michael Schumacher (no changes)
1996
WDC is determined in round 16 of 16 (no changes)
WDC is Damon Hill (no changes)
1997
WDC is determined in round 17 of 17 (no changes)
WDC is Jacques Villeneuve (no changes)
1998
WDC is determined in round 16 of 16 (no changes)
WDC is Mika Häkkinen (no changes)
1999
WDC is determined in round 16 of 16 (no changes)
WDC is Mika Häkkinen (no changes)
2000
old scheme: WDC determined in round 16 of 17
new scheme: WDC determined in round 17 of 17
WDC is Michael Schumacher (no changes)
2001
old scheme: WDC determined in round 13 of 17
new scheme: WDC determined in round 14 of 17
WDC is Michael Schumacher (no changes)
2002
old scheme: WDC determined in round 11 of 17
new scheme: WDC determined in round 12 of 17
WDC is Michael Schumacher (no changes)
2003
WDC is determined in round 16 of 16 (no changes)
old scheme: WDC is Michael Schumacher
new scheme: WDC is Kimi Räikkönen
2004
old scheme: WDC determined in round 14 of 18
new scheme: WDC determined in round 17 of 18
WDC is Michael Schumacher (no changes)
2005
old scheme: WDC determined in round 17 of 19
new scheme: WDC determined in round 19 of 19
WDC is Fernando Alonso (no changes)
2006
WDC is determined in round 18 of 18 (no changes)
WDC is Fernando Alonso (no changes)
2007
WDC is determined in round 17 of 17 (no changes)
WDC is Kimi Räikkönen (no changes)
2008
WDC is determined in round 18 of 18 (no changes)
old scheme: WDC is Lewis Hamilton
new scheme: WDC is Felipe Massa
2009
old scheme: WDC determined in round 16 of 17
new scheme: WDC determined in round 17 of 17
WDC is Jenson Button (no changes)
2010
WDC is determined in round 19 of 19 (no changes)
WDC is Sebastian Vettel (no changes)
2011
old scheme: WDC determined in round 15 of 19
new scheme: WDC determined in round 16 of 19
WDC is Sebastian Vettel (no changes)
2012
WDC is determined in round 20 of 20 (no changes)
old scheme: WDC is Sebastian Vettel
new scheme: WDC is Fernando Alonso
2013
WDC is determined in round 16 of 19 (no changes)
WDC is Sebastian Vettel (no changes)