The question arises when you come into a new leadership role at a organization. If the organization or department is failing do you rule with a iron fist and start firing people one by one? Do you listen to what your boss says when they say the department needs to be completed restructure or cleaned out?
The most successful leaders don’t do any of this. First you need to get know what sort of staff you have and get them to follow you. Most unsuccessful organizations or departments are unsuccessful because of there leadership. Sure after a while you may need to fire or layoff some people, but first you need to get them to follow you and put people in positions that they can thrive in. Mass layoffs or firings without knowledge of the people you have will turn the rest of the company against you and no one will want to work for you. You are setting yourself up for failure, everyone has good talents that will fit your goals as long as you take the time learn what those talents are and take the time to fit in.
Change is good, but radical change without taking a look at what you already have can be very counterproductive to what you are trying to accomplish.