Basically, Hollywood has already said everything I think.
As for Miscast; That's a bit of an apocalyptic view, don't you think? I'm also quite worried about his health and all that jazz, but I honestly don't think it's that bad. If Yoshiki was really in a very, very bad situation (I'm not even going to comment on the 'death' possibility) all the shows would be already cancelled; with or without a plausible explanation. And just like it was said, I don't think Toshi would be so happily travelling around Japan, making announcements and working on cutesy side projects if his best friend was tied to a hotel bed, paralysed.
I believe the only thing to blame is the management; a clear announcement on what's really going on would end up with stupid rumors and avoid possible waste of money. That is the part of the story that I consider regrettable: it's been over a week since rumours started & it's less than a month before the concert in question. Considering the amount of messages that are everyday posted to X's myspace, JRR etc., they are probably sick of knowing what the fans are worrying about. The least they could do is make an official announcement.
Plus, we're all grown people and I believe nobody is going to blame Yoshiki for having health problems. If somebody does, then I suggest that they reconsider their status of "fans". It's sad and upsetting that this things happen, of course. But we have to face things like they are: without people, there's no music. If a member of the band is not able to do their job, there's not much that can be done but hope that he gets better.