Here's my 2 cents. I'm sure to get flamed, but here goes...
First off, let me say I feel for the families of the woman and the little boy who died. They are in my thoughts and prayers.
Second: People are injured at theme parks around the world. Not just Disney. Like I've said in a previous thread, I live near the Mall of America and there have been at least 3 deaths there. One teenager fell off an escalator, a 7-yr old boy jumped off the flume ride, a 8 yr-old girl died on the "screamin' eagle". Now, Mall of America is an extremely watered down theme park ride-wise. The worst ride there is called the "Axe" and there is no way I'd go on it. I remeber once that thing got stuck upside down for over an hour. Those people were slightly ill after getting down!
But I digress... My point is tragedy happens everywhere. People die every day. Now before you start chucking tomatoes at me, you know this is true. I lost my mom to cancer so don't start calling me insensitive. We all have to deal with death at some point. Now that being said, I agree that death and disney just don't connect in my brain. Disney is such a happy, magical place. But it's still a place that people congregate and eat, have fun, cry, sleep, and yes some do die. That's part of the human condition.
Now that I have that off my chest, here's my 2 cents about Mission Space. I rode it once. I am free of serious medical conditions. It was an interesting ride and I was sick for the rest of the day. Was this MS fault? Maybe, but I doubt it. I'm fully aware that I get motion sickness easily and I should have known better with the warnings posted. Now I'm not saying that this little boy or the woman knew about any existing conditions (and we're not sure the woman had one, but I'm guessing she did), but the warnings are there. Why do I say this so blatantly? If your not willing to risk it, why ride it? Just because it's there doesn't mean Disney is making you ride it. It's like the whole "would you jump off a bridge if all your friends did?" spiel. Some people really enjoy this ride. And that's OK. Some people really enjoy sky-diving, too.
Here's the point I'm trying to make:
You don't have to ride it. And if ridership goes down, disney will probably start rethinking the ride. Again just my two cents, and here come the tomatoes!
BTW, if your up for a little light reading, here are accidents that happened at the other parks:
http://www.themeparkinsider.com/reviews/walt_disney_world's_magic_kingdom/accidents/
http://www.themeparkinsider.com/reviews/epcot/accidents/
http://www.themeparkinsider.com/reviews/disney-mgm_studios/accidents/
http://www.themeparkinsider.com/reviews/disney's_animal_kingdom/accidents/