First, we should note that there will be different specific politics to any specific administrative reform. We cannot say that the politics surrounding administrative reforms will always be exactly the same. That said, there are some generalizations that we can make regarding the politics of administrative reforms.
The main thing that we can say is that there will always be resistance to administrative change from many of the people in an organization. Bureaucracies of all sorts (whether they be governmental or private sector) tend to be resistant to change. The people who work in those bureaucracies become accustomed to the way things have always been done and they are not likely to welcome any major changes to the way in which they have been administered. Therefore, there will typically be resistance to administrative reforms.
However, there will also be some support. There will typically be support from people who have not necessarily prospered under the existing administrative regime. There may be support from outside the bureaucracy. For example, there may be support for change in upper management even though middle management resists.
Thus, the typical political dynamic here is that there will be support for change from outside the mainstream of an organization, but its mainstream will typically resist administrative reform.