"In cases where the Unabridged Birth Certificate is in a language other than English, it must be accompanied by a sworn translation". If other countries start applying this, you will need to get a sworn translation in lots of languages. What you need is a birth certificate equivalent to the International Driving Permit, which provides multiple-language translation.
The problem would be partially solved if passports for under-18's had their parent(s) or guardians listed.
"When a child travels with only one parent, he/she will require a passport, Unabridged Birth Certificate, an affidavit in which the absent parent gives consent for the child to travel and a court order granting full parental responsibilities, or legal guardianship of the child, or the death certificate of the absent parent." - That is heavy. It says "consent of the other parent AND a court order". Surely it should be "OR". What if you have full custody, and can't contact the other parent, or they say "No"?