You're in large company if you're having trouble with Peace. I'm spading mine this year and putting in new stock, virus-indexed, from Europe.
The strain of Peace that has been propagated here in the United States is a pale shadow of the European Peace. I believe that the problem is similar to over-popular dog breeds; too weak a strain. I bought my new Peace roses from Heirloom Roses, this is the first year they have offered them.
Peace also seems sensitive to salt build-up in the soil from fast-grow fertilizers, my friends who use organics have better Peace roses than those who have grown roses for a long time with chemical fertilizers. They need a rose feed which has low nitrogen with sulfer of potash in late winter or their growth is soft and a bug-feast.