So often we treat the implementation of plans as self-evident. The plan states that the departments will do X and Y by December 1. By heavens, they should forge ahead and do it.
Unfortunately, many of the executives and managers do not know how to implement the plan and are embarrassed to admit their ignorance. [Learning to admit ignorance is a major life skill.]
In some cases, these key actors think they know but they don't. In others, they will cobble together an approach that may cause more problems than the plan was devised to resolve.
It is so easy to believe that guidelines are clear and the required passion is present. Planners have been known to fall in love with their product. They cannot grasp the indifference of those who simply want to do whatever is necessary to get the externally-imposed requirement out of the way so the "real job" can be done. They are shocked when deadlines are missed and important actions are not taken.
All plans require translation and drill until it is evident that the team knows the language and accepts the priorities. Up to that point, a plan is simply a document. We may as well write them in Latin.