[sixstringtheory]

That deals with responding to reviews of your app, not an ability to leave a review for iOS itself. Either way, I don't think the average consumer will understand that they've lost data because of a bug in a new filesystem. And if you are an app with appreciable market share and something goes wrong, I doubt one would be able to mitigate a crush of negative reviews.

[thecosas]

If you're an app with a large marketshare, the responsible thing would be to do testing with the betas to search out potential bugs.

Doesn't cover all instances, but should help with any MAJOR bugs that would come up.

[warcher]

You only get the level of engineering investment that somebody is willing to pay for.