I have an idea. Let's try to look at this logically for once. It was risky to put Castillo on that side of the ball. He did have a learning curve, as did the defense due to all the new faces. However, take a look at the facts:
1. Castillo hadn't coached defense for years, and an adjustment period was expected.
2. Castillo is one of the best teachers in the game, and understands that practice, repetition, and muscle memory are the ingredients to "playing fast."
3. The Eagles were #1 in sacks.
4. The Eagles were #8 in total defense.
5. They didn't have an off-season to gel considering all the new coaching and players.
6. They showed A LOT of improvement as the season progressed.
You see poor decisions and bad performance through your pessimistic view. I see taking a risk on Castillo, when he knew he would be heavy criticized and even laughed at, as good leadership and guts. I see potential in Castlo and this defense, and if you look at the facts you should be able to see it as well.