When making the transition to manager, there is an increase in responsibility and also an internal increase in your own expectations to do a good job. Often this translates into overmanaging.
Until the day when BCA mandates that BIM managers should possess a Specialist Diploma certificate, the qualifications of BIM managers are still vague. Anyone can "grow" into a BIM manager with some form of self-study ...
I would like to put forward the argument that the position description "BIM Manager" is becoming too generic, too non-descript to actually be useful in evaluating or determining what a BIM person actually does.