Best solution to political dynasties is to punish corruption. Why do you think there are political dynasties? It's because these people are treating government posts like a family business, there for the milking. As soon as we start sending corrupt officials to jail or better yet, executing them, you remove the incentive to run for office. What's the use of having family dynasties in politics when there's no money in it for the family?
The main cause of political dynasties here, as it is in many third world countries, is the easy money that attracts the maggots and worms to the honey pot... give the maggots a flogging and they will run away!