It's pretty common for people to be against change, even if that change is just you being the new head honcho.

It sounds like this is a head director position? If that is, you'll always have people scrutinize you. You're in a position of power, that alone can make others angry and they'll want to punch up.

People will also see the best in something once it's done and over, but I guarantee if that director came back they would be happy for a couple of months then remember why they were upset (or be too proud to admit it to you).

How long have you been teaching? Is this the first time you've changed schools? Were you a high school director in the past school?