What makes a good livestock guarding dog?
I would say it would have to be the right genetics (meaning good working lineages resulting from adequate functional selection) potentiated by the right environment (proper bonding and training) and enabled by good animal welfare.
The role of the farmers/owners is crucial to optimize the bonding process and the physical and behavioural development of the dogs, and to prevent and correct any problems that may occur.
There is a lot of information available on how to select, train and maintain these dogs in different contexts, so they can grow up to become good working dogs: attentive, trustworthy and protective of the livestock, well integrated into the community and with existing activities (e.g. tourism, hunting).
There is also a nice article on issue 15 of the CDPnews – Carnivore Damage Prevention News that discusses solutions to perceived limitations on the use of these dogs. It is available here: https://www.protectiondestroupeaux.ch/en/cdpnews/