Humph. This is a tough one. On the one hand I like @david-a‘s suggestion of Vettel not crashing into Fuji, and could instead hang on for a win. Or maybe one of the early 2009 races, so that Vettel would’ve been 2009 WDC :P
Another one would be changing the events of 30 years ago actually. Salut Gilles. Much as I am a Senna fan; I actually think he won’t be held in as high regard as he is now, had Imola 1994 not happened.
I’m surprised no one has talked about the pitlane entry in China 2007…