The biggest negative about ruling by fear is you never will get true and honest opinions therefore you will end up in your own bubble.
Unfortunately fear will allow you to rise to power , it has proven so through out history but those never end well.
I have witnessed it personally at the work place, I have worked under the bullies and those that treated others wrongly and they never lasted.
The sad thing was watching others getting treated with dis respect or talked about behind their back. In some cases I spoke my peace in others I may have had to take a back door route in fear of retribution. If I wanted to truly help others that were being abused I needed to keep my job so I could help where I could.
I was always secure enough in myself that the bully normally stayed away from me, at least face to face, they would still try to manipulate me through others or their actions so my saving grace was to just to my job and make it so my worth to the work place and ultimately to them was high enough that they benefited from me.
The sorry thing they just all lived in their own world because no one would ever challenge them in fear of retribution. If you disagree with them they say you are negative or that you are not being a team player but by speaking out you are trying to be honest and improve the situation but they do not see it that way. So they surround themselves with their yes men and women, at least to his or her face, and they continue to think they are the greatest thing since sliced bread.
Ruining by fear and/or intimatation will never sustain.