Perhaps the mistakes the FBI made were not in vain, but they wee made. The FBI agents involved were seeking these specific killers. When they found them they, weren't wearing vests, they lost guns and glasses in the auto accident, and then were without long arms, despite knowing it was the MO of the perps to carry them.

One speaks ill of the dead at a certain risk; but those officers were not ready for what happened, despite the fact that finding and arresting those very suspects is what they were attempting to do.

A "plan" that has disastrous consequences when it works is not much of a plan. It is good they do things differently now. Too bad good men had to die and be injured to learn those lessons.