Thanks for all the info guys.
But I still have my original question: If I'm not mistaken, Asashoryu now has the highest ranking ever since the start of Doitsuyama's ratings table (1989). Since the ratings should also take the level of the opposition into account, does that make him 'best', or does it mean the system should be adjusted, or what?
There have been many discussions on this board about Asa vs. Taka vs. Chionofuji vs. Taiho, and with his current rating, his peak form seems to lie above that of Taka, at any rate. The question is how long he can maintain his present form, but in the hypothetical Asa-at-his-peak vs. Taka-at-at-his-peak, this seems to suggest that Asa should win.