There is, of course, no objective answer to this question. Childrens' rights advocates tend to argue that the Court did not do a good job while those who believe that parents' rights and childrens' rights are more closely aligned are more likely to say it did.
To say that Santosky did a bad job of protecting children's rights, we have to argue that it is in a child's best interests to be removed from home whenever it seems likely they are being neglected or abused. That is, we have to argue that it is more important to get them out than to be very sure that they are being mistreated. While this is not an unreasonable argument, it is also not an objective truth. One can also argue that it is in a child's interest to stay with its parents rather than being put in foster care in hopes that it will be adopted.
My opinion is that the "clear and convincing" standard is good for children. It allows them to be taken away from their parents when necessary, but does not make it too easy to destroy this important relationship.