The great surprise here is that many successful CAD managers have little or no programming experience when they start out. In an AutoCAD landscape the ability to edit menu files or do some light AutoLISP programming is certainly a plus but not a requirement. While I would recommend that any CAD manager pursue some education or practical experience in programming, the simple fact of the matter is that programming skills don't seem to correlate to being a great CAD manager. Managerial skills include hiring, staff development, budgeting, new technology implementation and so forth. No amount of AutoLISP programming can help when its time to hire staff or to rampup to maximum worker productivity.
Most CAD managers move up from the power-user, technologist level into management.
The best CAD managers realize early on that they have the technical skills they need but will have to learn more about management. The key here is the realization that becoming a CAD manager is a real shift in your career. If you anticipate the demands of the transition and embrace them as a challenge, you'll move into management much more smoothly. CAD management is much more dependent on being able to communicate effectively than on being a CAD power user. Effective writing tends to be the single, most-important communication skill you can master and the ability to deal with people directly and personably in clear language is key to effective staff management.