This is a highly emotionally charged and complicated issue. Off shore drilling is a delicate operation and done so under strict guidelines with tremendous safeguards to prevent such a disaster and had done a great job for over 40 years with nary a problem.
Guess who directs these drilling operations?? Yeppers! The Government!! So who should take the blame?? Yeppers the Government!! IMO nothing needs to really be changed. The manufacturer of one of the shutoff valves may have some culpability.
Turn in the keys to your SUV and gas mower and that will solve the problem instantly other than that, but other than that not much more can be engineered into the offshore drilling process and if could it would have.