Those two games showed how the team was built, meaning, when the oline and TAYSOM was healthy, the offense was able to run how it was built. Even after McCoy went down, they were able to operate how they wanted, evident by the first couple of drives in the Falcons game.
Now with the injuries mounting, it probably won't look the same even when Taysom returns, but we all see how it looks when there's somewhat good health. As for the defense, I think it's a combination of coaching, age, and lack of effort, especially the last 3 games.