1. His personal life is in shambles.
2. He is being plagued by chronic injuries.
3. His physical and mental condition has deteriorated.
4. The kyokai is on the verge of a roids witchhunt.
5. He is being overshadowed by a rival yokozuna.
6. His primary life interests seem to lie outside sumo.
7. There is a new rijicho who obviously has a strong dislike for him.
8. He is being verbally savaged by most of the other oyakata.
9. He is being hounded by a hostile press.
10. He is financially well off with many business interests.
11. He longs for Mongolia where he is most comfortable (and widely accepted).
Other than that, everything is fine.
Haven't heard much about 1 or 2. Three seems to be speculation at best, at least the mental part. Competition seems somewhat better than what it was a few years back though. Maybe that has something to do with it. I don't see 5 at all. Hakuho, even though he is younger, has not come close to show the kind of skill and consistency Asa has shown. Perhaps its the "humbleness" the japanese like?
As much as i hate to admit it, 4 seems kinda "valid".
Care to elaborate on 7, 8 and 9?
What ever it is, sumo won't be the same if he retires.