Managers - Anyone who has worked at Google will agree that the managers are below par. I wouldn't admit is is true in all cases. However, the average manager at Google, just doesn't have the leadership skills required.
Lack of transparency from mid management - While the top management is quite clear/transparent with it communications/plans, it is totally absent from mid-management. Again, the issue is with managers. Most managers are busy driving their personal agenda, and they often neglect others' growth in the company. Promotion criteria is totally biased towards 'favourable employees' being more favoured.
Career prospects - Google isn't a place for long term career planning. After a point in time you are stuck, and your role leads you no where, and some of the operational-role based teams aren't sure about the direction of the team. Discussing this with your manager is of no help because the manger simply doesn't have the time for such career enhancement talks.
Overall, Google is headed towards being any other big organization with bureaucracy ranging from lunch table to promotions to reviews.