I've had my PE license for over 20 years now.  I do not actively practice as a PE, but as a sales engineer selling power plant equipment.  A continuing education requirement will make someone somewhere feel likey they're doing their job and making professional people do what they should already be doing - continuing to conscientously learn, use and hone their skills.  If you are not continuing to do this actively already, you are not in the vanguard of your profession and deserve what you get - stagnation.  The market will also act as an excellent mechanism for finding and rewarding or punishing professional people who are or are not doing it right.  Government does not have a role to play here, except for those who need a reason to feel good.  There are plenty of burning issues to deal with but this ain't one of 'em.