To answer my own retorical question -- in Wijk aan Zee 1999, Kasparov started with a draw and then won seven in a row (Van Wely, Yermolinsky, Topalov, Reinderman, Piket, Shirov and Kasimdzhanov), 7.5/8, before losing to Ivan Sokolov.
So let's see if Carlsen can do better :-)
I'm not nearly strong enough to see a game and say, hey that's Kasparov influence right there.
Of course there's the obvious that everybody jumps on (he's played the Scotch and the Najdorf). But in general his style is supposed to be much more like Karpov than Kasparov, and the way he's winning is not by stunning novelties and extremely deep calculation, but by relentlessly setting problems for his opponents and never letting go of a better position.
And anyway, when's the last time Kasparov got 4.5/5 in a field like this? But of course it's better to compare stats like that after the whole ten rounds. He may yet lose a few.
Anyway, I don't believe that a soccer scoring system would have changed anything about the other results.