It seems obvious that the same rating system is not appropriate in these different cases. So credit-rating agencies should make it clear that their ratings for complex, opaque securities ought not to be used in the same manner as ratings for conventional bonds issued by singlenames. There have been calls for stricter regulations for credit-rating agencies.
After significant market events, it's always appropriate to review the regulations and our roles as governments, central banks, and regulators in terms of these ratings. But I would caution against any knee-jerk regulatory response.