Powerful good guy can work (see e.g. Singapore); usually the problem is when the powerful good guy retires another powerful guy is the successor, but you dont h

Powerful good guy can work (see e.g. Singapore); usually the problem is when the powerful good guy retires another powerful guy is the successor, but you dont have any checks and balances to make sure if they are good or not. So after a few transitions you might end up with a powerful bad guy.