There are a lot of reason.

The first, I have started thinking about it when people suggested in a few months ago.

Then, while I was gone, a certain person caused three staff members to leave, and that ruined the state of two LEO departments.

Three, the policies of all three departments could be improved on.  The policies they put out were either not worked on with others in mind.

Four, I saw that staff members in their departments failed to have proper staff meetings to help the members be satisfied, and to improve the department, even after many amounts of reminders.
Four, I saw that staff members in their departments failed to have proper staff meetings to help the members be satisfied, and to improve the department, even after many amounts of reminders.

Five, the departments, with so many that are similar, making sure that each one is doing their job properly, of making sure that members are happy, was not good, due to the feedback given.

Six, there were complaints that could only be fixed via there being one department that could all be managed centrally, and not have different departments interfere with divisions.  It was very present between HP and SO.

Seven, there were many complaints of department down talking, specifically from LEO to LEO, that was address in the past two community meetings, and didn't improve.  In game, in the county usually, there are arguments over where someone can go.

Eight, it gives the members more opportunities to have people in their divisions, and for the divisions to be there.

Nine, PD is still not getting enough members to sustain more advancements in the department.  SO is growing, but lacking staff members.  HP has some issues internally with managing.

Ten, every department including Fire, Civilian, and communications, are being reformed in accordance to the complaints we have received, and feedback from members.  Since this is happening with them, LEO should as well, however the changes would have to be made to all three departments, so one department also makes it easier on top of all the other reasons.

Eleven, it makes spreading out easier, and gives the city more units, because they can be in a state department and patrol in the city, meaning more civilians there too.

There are some more.