Never want to see any rider injured, but casey shouldn't have got injured if he wanted to win the championship, same as 1992 and 1993 for mick doohan; as casey himself said "that's racing". I hope the long term consequences of stoner's injury are less severe than they were for doohan.
Maybe he would have had the crash anyway, but going for the win rather than settling for second and the championship lead at sachsenring and the possible pressure resulting from that may have been very costly, since the bike looks really good now and looks to have the advantage on the yamaha now as zootalaws says; no talk of chatter recently. Again, he decided to go for the last lap pass, not pedrosa or lorenzo.
I agree with all of this. You have to finish to win. And stay healthy to win a WC. It's a shame he did get injured though, he would have been fighting for first if he hadn't. In that sense Jorge and Dani are lucky. Not that I really want to open the can of worms that is "lucky".