The four specific areas that we want to mobilize in the Olympic lifts are:
Ankle
Hip
Thoracic spine
Shoulder external rotation
A lifter that doesn't spend time mobilizing these areas could have problems executing the lifts with any semblance of good technique. A lack of mobility in these areas can lead to compensatory patterns that could cause injury.
Cressey doesn't miss anything. Stuff he didn't miss in 2010 includes the myth of symmetry, zones of convergence, the complete overuse of barefoot training, and the dangers of zits.