I would think a higher divorce rate may mean greater freedom to get out of a dysfunctional marriage, or a decrease in people's ability to couple effectively, or a decrease in societal norms regarding commitment, or lots of things.
What causes me to think its a net negative is that often you have children who get hurt in the process. I think it's, on average, better for a couple to stay married if they have children and try to work things out. The rising acceptance of divorce culturally causes some to forgo the hard work necessary to rebuilding the marriage.
Obligatory caveat so people don't get butthurt: yes, sometimes divorce is inevitable, including abuse, neglect, significant negative influence on spouse and kids...
Back on topic, the 'American Dream' of the 50's was wrapped around a nuclear family. Now it's more about achieving individual goals and self-actualization.