Black and white and perfectionism isn't good. It's not good for your daughters... hopefully, your efforts will make enough of a difference for them in the long run.
My husband used to see everything in black and white, and much of it had to do with simple fear. It takes a lot of courage to live with the fact that there are many shades of gray!
How is her relationship with her parents? My mother in law is mentally ill and has an entire family tiptoeing around her. My husband simulataneously hated her and was like her, because he saw her as being the one with all the power. He loves his dad, but the man is the most whipped person I have ever met. I used to be very submissive, so it was easy for me to be the whipped partner and my husband to be the one with all the power and control. Until I decided I wasn't a doormat after all.

When he saw he was acting just like his mother, he (very slowly) began to change. But it has literally taken YEARS of love, patience, and good counsel.
If your wife can come to realize that your daughter's relationships will be effected by what they see modeled... how big of an influence she has over them through her everyday behaviors... hopefully, she will try to be more open to how she can improve. They are at an age and in a society where they are very vulnerable to things like eating disorders, etc.
There are two books I can recommend by Mary Pipher.
Reviving Ophelia is something your wife should read... she may see herself in the book. All the women I know who have read it found it did them a lot of good, in terms of getting to the root of their own hurt and anger. Then there is
Rebuilding Our Families: In The Shelter Of Each Other that is about keeping a family strong and healthy despite outside influences that can weaken us. And none of it is religious or preachy, which is a plus to me.
I truly wish you success in your efforts... we have three kids, ages 16. 10, and 5... and the best thing we can do for them is to love each other. I know you know that, too!