Flaws I saw
Let me be the first (a joke) to point out that there were numerous plot holes in this movie. The planets would have to have aligned for Crawford's plan to work. If any one thing goes wrong, the whole thing fails.
1. What if the initial cops on scene did not set up a perimeter around the house, and instead burst in and took him into custody?
2. What if Nunally was not the negiotiator who came to the house?
3. What if Nunally had not gone up to the house to negotiate face to face (real life negotiators don't do this), and instead did it over the phone?
4. What if Nunally knew this was the residence of his mistress, and did not involve himself in the negotiations process.
5. What if the two SWAT guys who went up with Nunally did not wait outside?
6. What if Nunally would not agree to put his gun down? Or would only agree to HOLSTER his own gun, instead of putting it down? Or what if he gave it to one of the SWAT guys outside instead of putting it down.
7. What if Nunally was able to keep himself calm when seeing his mistress shot, and did not allow for the guns to be switched back.
Crawford seems like a genius only because none of these things happened.
In the conversation Crawford had with Beachum when he spoke of finding the flaws in the eggs, he mentioned finding the flaw in Beachun (that he was a winner) and made it seem as though he would exploit that flaw to beat him. In reality, any attorney--winner or not--would have lost that case with the way Crawford was (miraculously) able to pull it off.