If you look at the numbers Valerie is a late 50's and 60's name and then saw a brief revival in the 80's. The only Valerie I've ever known well was a friend of my mother and she was either born in the 50's or 60's. You're right that Valerie has never been super popular. At its most popular year which was 1959 it was at number 60.
I personally have always liked the name Valerie. But when I was growing up I kept meeting people who told me that they hated it and I've never understood why. I've only met a few people who like the name Valerie. But I haven't asked in a long time, maybe now people don't view it as being dated and maybe since people have been loving V names it will see a come back.