You can crunch all of the numbers, get the arrows pointing upward on the charts, and still not persuade your audience.
There are always The Powerful Intangibles that can mean more to others than all of your logic. Focusing solely on the hard items and not the soft invites disaster. Fortunately, those soft items that cry out for attention usually fall into one category: Status.
Propose a change that is perceived to diminish the status of a person and you should count on a reaction akin a wounded wolverine's response to a poke with a sharp stick. This will occur despite your ability to show all sorts of marvelous reasons why the person should be supportive. Attack my status and you attack me, personally and deeply.
An example can be found in the flare-ups that occur when job titles and reporting relationships are altered. The change agent may think such matters are trivial but they aren't to the person who boasts of a direct line to the boss or who doesn't want to tell the folks at home that his or her title has shifted from "director" to "coordinator." Pointing out the extra pay and the fact that authority has not changed will not score any points. A Great Intangible has been touched.
That's why any proposed changes, both in substance and procedure, should be scrutinized for status issues. It is important to be logical, but not coldly so.