Disadvantages of a single administrator checking all file permissions

Disadvantages of a single administrator checking all file permissions

What would be the security disadvantages of a single administrator
checking every file permission in a network of computers? Obviously this
is a theoretical question.
I'm thinking that the fact that one entity has control over every file in
the system would mean that:
a) The administrator could accidentally or purposely cause harm to
important files.
b) A malicious entity could gain access to the administrators account and
cause significant damage to the whole system
Is there anything else I should consider? I need to think about this in
terms of likelihood or extent of damage caused by an attack.
Thanks